Richard L. Stone (argued), Ronald S. Cohen, Carlo F. Van den Bosch, Sheppard, Mullin, Richter & Hampton, Los Angeles, California, for the plaintiff-appellant.

 Dennis G. Martin (argued), Christina L. Johnson, Willmore F. Holbrow, III, Blakely, Sokoloff, Taylor & Zafman, Los Angeles, California, for the defendant- appellee.

 Appeal from the United States District Court for the Central District of California;  Carlos R. Moreno, District Judge, Presiding.  D.C. No. CV-98- 09074-CRM.

 Before:  CANBY, O'SCANNLAIN, and WARDLAW, Circuit Judges.

 O'SCANNLAIN, Circuit Judge:

 We must venture into cyberspace to determine whether federal trademark and unfair competition laws prohibit a video rental store chain from using an entertainment-industry information provider's trademark in the domain name of its web site and in its web site's metatags.

I

 Brookfield Communications, Inc. ("Brookfield") appeals the district court's denial of its motion for a preliminary injunction prohibiting West Coast Entertainment Corporation ("West Coast") from using in commerce terms confusingly similar to Brookfield's trademark, "MovieBuff."  Brookfield gathers and sells information about the entertainment industry.  Founded in 1987 for the purpose of creating and marketing software and services for professionals in the entertainment industry, Brookfield initially offered software applications featuring information such as recent film submissions, industry credits, professional contacts, and future projects.  These offerings targeted major Hollywood film studios, independent production companies, agents, actors, directors, and producers.

 Brookfield expanded into the broader consumer market with computer software featuring a searchable database containing entertainment-industry related information marketed under the "MovieBuff" mark around December 1993. [FN1] Brookfield's "MovieBuff" software now targets smaller companies and individual consumers who are not interested in purchasing Brookfield's professional level alternative, The Studio System, and includes comprehensive, searchable, entertainment-industry databases and related software applications containing information such as movie credits, box office receipts, films in development, film release schedules, entertainment news, and listings of executives, agents, actors, and directors.  This "MovieBuff" software comes in three versions--(1) the MovieBuff Pro Bundle, (2) the MovieBuff Pro, and (3) MovieBuff--and is sold through various retail stores, such as Borders, Virgin Megastores, Nobody Beats the Wiz, The Writer's Computer Store, Book City, and Samuel French Bookstores.
 

FN1. The parties quibble over whether the exact date was in December 1993 or in January 1994, but this dispute is irrelevant.

 Sometime in 1996, Brookfield attempted to register the World Wide Web ("the Web") domain name "moviebuff.com" with Network Solutions, Inc. ("Network Solutions"), [FN2] but was informed that the requested domain name had already been registered by West Coast.  Brookfield subsequently registered "brookfieldcomm.com" in May 1996 and "moviebuffonline.com" in September 1996. [FN3]  Sometime in 1996 or 1997, Brookfield began using its web sites to sell its "MovieBuff" computer software and to offer an Internet-based searchable database marketed under the "MovieBuff" mark.  Brookfield sells its "MovieBuff" computer software through its "brookfieldcomm.com" and "moviebuffonline.com" web sites and offers subscribers online access to the MovieBuff database itself at its "inhollywood.com" web site.
 

FN2. Pursuant to a contract with the National Science Foundation, Network Solutions was, at all relevant times, the exclusive registrar of certain domain names, including those ending in ".com" The intricacies of the  Internet and the Web are explained in detail in Part II.

FN3. It also registered "inhollywood.com," but exactly when it did so is unclear from the record.

 On August 19, 1997, Brookfield applied to the Patent and Trademark Office  (PTO) for federal registration of "MovieBuff" as a mark to designate both goods and services.  Its trademark application describes its product as "computer software providing data and information in the field of the motion picture and television industries."  Its service mark application describes its service as "providing multiple-user access to an on-line network database offering data and information in the field of the motion picture and television industries." Both federal trademark registrations issued on September 29, 1998.  Brookfield had previously obtained a California state trademark registration for the mark "MovieBuff" covering "computer software" in 1994.

 In October 1998, Brookfield learned that West Coast--one of the nation's largest video rental store chains with over 500 stores--intended to launch a web site at "moviebuff.com" containing, inter alia, a searchable entertainment database similar to "MovieBuff."  West Coast had registered "moviebuff.com" with Network Solutions on February 6, 1996 and claims that it chose the domain name because the term "Movie Buff" is part of its service mark, "The Movie Buff's Movie Store," on which a federal registration issued in 1991 covering "retail store services featuring video cassettes and video game cartridges" and "rental of video cassettes and video game cartridges."  West Coast notes further that, since at least 1988, it has also used various phrases including the term "Movie Buff" to promote goods and services available at its video stores in Massachusetts, including "The Movie Buff's Gift Guide";  "The Movie Buff's Gift Store";  "Calling All Movie Buffs!";  "Good News Movie Buffs!"; "Movie Buffs, Show Your Stuff!";  "the Perfect Stocking Stuffer for the Movie Buff!";  "A Movie Buff's Top Ten";  "The Movie Buff Discovery Program";  "Movie Buff Picks";  "Movie Buff Series";  "Movie Buff Selection Program";  and "Movie Buff Film Series."

 On November 10, Brookfield delivered to West Coast a cease-and-desist letter alleging that West Coast's planned use of the "moviebuff.com" would violate Brookfield's trademark rights;  as a "courtesy" Brookfield attached a copy of a complaint that it threatened to file if West Coast did not desist.

 The next day, West Coast issued a press release announcing the imminent launch of its web site full of "movie reviews, Hollywood news and gossip, provocative commentary, and coverage of the independent film scene and films in production."  The press release declared that the site would feature "an extensive database, which aids consumers in making educated decisions  about the rental and purchase of" movies and would also allow customers to purchase movies, accessories, and other entertainment-related merchandise on the web site.

 Brookfield fired back immediately with a visit to the United States District Court for the Central District of California, and this lawsuit was born.  In its first amended complaint filed on November 18, 1998, Brookfield alleged principally that West Coast's proposed offering of online services at "moviebuff.com" would constitute trademark infringement and unfair competition in violation of sections 32 and 43(a) of the Lanham Act, 15 U.S.C. §§ 1114, 1125(a). [FN4]  Soon thereafter, Brookfield applied ex parte for a temporary restraining order ("TRO") enjoining West Coast "[f]rom using ... in any manner ... the mark MOVIEBUFF, or any other term or terms likely to cause confusion therewith, including moviebuff.com, as West Coast's domain name, ... as the name of West Coast's website service, in buried code or metatags on their home page or web pages, or in connection with the retrieval of data or information on other goods or services."
 

FN4. Brookfield also asserted a trademark dilution claim under 15 U.S.C. § 1125(c) and California state law trademark and unfair competition claims.

 On November 27, West Coast filed an opposition brief in which it argued first that Brookfield could not prevent West Coast from using "moviebuff.com" in commerce because West Coast was the senior user.  West Coast claimed that it was the first user of "MovieBuff" because it had used its federally registered trademark, "The Movie Buff's Movie Store," [FN5] since 1986 in advertisements, promotions, and letterhead in connection with retail services featuring videocassettes and video game cartridges.  Alternatively, West Coast claimed seniority on the basis that it had garnered common-law rights in the domain name by using "moviebuff.com" before Brookfield began offering its "MovieBuff" Internet-based searchable database on the Web. In addition to asserting seniority, West Coast contended that its planned use of "moviebuff.com" would not cause a likelihood of confusion with Brookfield's trademark "MovieBuff" and thus would not violate the Lanham Act.
 

FN5. West Coast applied for a federal trademark registration for this term in 1989, which issued in 1991 and became incontestable in 1996.  West Coast purports to have spent over $15,000,000 on advertisements and promotions featuring this mark.

 The district court heard arguments on the TRO motion on November 30.  Later that day, the district court issued an order construing Brookfield's TRO motion as a motion for a preliminary injunction and denying it.  The district court concluded that West Coast was the senior user of the mark "MovieBuff" for both of the reasons asserted by West Coast.  The court also determined that Brookfield had not established a likelihood of confusion.

 Brookfield responded by filing a notice of appeal from the denial of preliminary injunction followed by a motion in the district court for injunction pending appeal, which motion the district court denied.  On January 16, 1999, West Coast launched its web site at "moviebuff.com." Fearing that West Coast's fully operational web site would cause it irreparable injury, Brookfield filed an emergency motion for injunction pending appeal with this court a few days later.  On February 24, we granted Brookfield's motion and entered an order enjoining West Coast "from using, or facilitating the use of, in any manner, including advertising and promotion, the mark MOVIEBUFF, or any other term or terms likely to cause confusion therewith, including @moviebuff.com or moviebuff.com, as the name of West Coast's web site service, in buried code or metatags on its home page or web pages, or in connection with the retrieval of data or information on other goods or services."  The injunction was to take effect upon the posting of a $25,000 bond in the district court by Brookfield.  We scheduled oral  argument on an expedited basis for March 10.

 West Coast thereupon filed a motion for reconsideration and modification-- seeking a stay of the injunction pending appeal and an increase in the bond requirement to $400,000--which we denied.  After oral argument on March 10, we ordered that our previously issued injunction remain in effect pending the issuance of this opinion.

II

... [The court gives an introduction to the Internet]

Oftentimes an Internet user will begin by hazarding a buess at the domain name, especially if there is an obvious domain name to try.  Web users often assume, as a rule of thumb, that the domain name of a particular company will be the company name followed by ".com." ...  A Web surfer's second option when he does not know the domain name is to utlize an Internet search engine.

...

...

   IV

To resolve whether West Coast's use of "moviebuff.com" constitutes trademark infringement or unfair competition, we must first determine whether Brookfield has a valid, protectable trademark interest in the "MovieBuff" mark.  ... [A] fundamental tenet of trademark law is that ownership of an inherently distinctive mark such as "MovieBuff" is governed by priority of use.

...

 It is uncontested that Brookfield began selling "MovieBuff" software in 1993 and that West Coast did not use "moviebuff.com" until 1996.  According to West Coast, however, the fact that it has used "The Movie Buff's Movie Store" as a trademark since 1986 makes it the first user for purposes of trademark priority.  In the alternative, West Coast claims priority on the basis that it used "moviebuff.com" in commerce before Brookfield began offering its "MovieBuff" searchable database on the Internet.  We analyze these contentions in turn.

A

 Conceding that the first time that it actually used "moviebuff.com" was in 1996, West Coast argues that its earlier use of "The Movie Buff's Movie Store" constitutes use of "moviebuff.com."  West Coast has not provided any Ninth Circuit precedent approving of this constructive use theory, but neither has Brookfield pointed us to any case law rejecting it.  We are not without guidance, however, as our sister circuits have explicitly recognized the ability of a trademark owner to claim priority in a mark based on the first use date of a similar, but technically distinct, mark--but only in the exceptionally narrow instance where "the previously used mark is 'the legal equivalent of the mark in question or indistinguishable  therefrom' such that consumers 'consider both as the same mark.' "  Data Concepts, Inc. v. Digital Consulting, Inc., 150 F.3d 620, 623 (6th Cir.1998)

...

We agree that tacking should be allowed if two marks are so similar that consumers generally would regard them as essentially the same.  Where such is the case, the new mark serves the same identificatory function as the old mark.  Giving the trademark owner the same rights in the new mark as he has in the old helps to protect source-identifying trademarks from appropriation by competitors and thus furthers the trademark law's objective of reducing the costs that customers incur in shopping and making purchasing decisions.  ...

 Without tacking, a trademark owner's priority in his mark would be reduced each time he made the slightest alteration to the mark, which would discourage him from altering the mark in response to changing consumer preferences, evolving aesthetic developments, or new advertising and marketing styles. ...

 The standard for "tacking," however, is exceedingly strict:  "The marks must create the same, continuing commercial impression, and the later mark should not materially differ from or alter the character of the mark attempted to be tacked."  Van Dyne-Crotty, 926 F.2d at 1159 (emphasis added) (citations and quotation marks omitted).  In other words, "the previously used mark must be the legal equivalent of the mark in question or indistinguishable therefrom, and the consumer should consider both as the same mark."  Id. (emphasis added);  see also Data Concepts, 150 F.3d at 623 (adopting the Van Dyne-Crotty test).  This standard is considerably higher than the standard for "likelihood of confusion," which we discuss infra.

...

 In contrast to cases such as Van Dyne-Crotty and American Paging, which were close questions, the present case is clear cut:  "The Movie Buff's Movie Store" and "moviebuff.com" are very different, in that the latter contains three fewer words, drops the possessive, omits a space, and adds ".com" to the end.  Because West Coast failed to make the slightest showing that consumers view these terms as identical, we must conclude that West Coast cannot tack its priority in "The Movie Buff's Movie Store" onto "moviebuff.com." As the Federal Circuit explained, "it would be clearly contrary to well-established principles of trademark law to sanction the tacking of a mark with a narrow commercial impression onto one with a broader commercial impression."  Van Dyne-Crotty, 926 F.2d at 1160...

 Since tacking does not apply, we must therefore conclude that Brookfield is the senior user because it marketed "MovieBuff" products well before West Coast began using "moviebuff.com" in commerce:  West Coast's use of "The Movie Buff's Movie Store" is simply irrelevant.

...

 West Coast makes a half-hearted claim that "MovieBuff" is confusingly similar to its earlier used mark "The Movie Buff's Movie Store." If this were so, West Coast would undoubtedly be the senior user.  See id. "Of course, if the symbol or device is already in general use, employed in such a manner that its adoption as an index of source or origin would only produce confusion and mislead the public, it is not susceptible of adoption as a trademark."  Hanover Star Milling Co. v. Metcalf, 240 U.S. 403, 415, 36 S.Ct. 357, 60 L.Ed. 713 (1916).  West Coast, however, essentially conceded that "MovieBuff" and "The Movie Buff's Movie Store" are not confusingly similar when it stated in its pre-argument papers that it does not allege actual confusion between "MovieBuff" and West Coast's federally registered mark.  We cannot think of more persuasive evidence that there is no likelihood of confusion between these two marks than the fact that they have been simultaneously used for five years without causing any consumers to be confused as to who makes what.  ... The failure to prove instances of actual confusion is not dispositive against a trademark plaintiff, because actual confusion is hard to prove;  difficulties in gathering evidence of actual confusion make its absence generally unnoteworthy.  See Eclipse Associates Ltd. v. Data Gen. Corp., 894 F.2d 1114, 1118-19 (9th Cir.1990); Sleekcraft, 599 F.2d at 353.  West Coast, however, did not state that it could not prove actual confusion;  rather, it conceded that there has been none.  This is a crucial difference.  Although there may be the rare case in which a likelihood of future confusion is possible even where it is conceded that two marks have been used simultaneously for years with no resulting confusion, West Coast has not shown this to be such a case.

 Our conclusion comports with the position of the PTO, which effectively announced its finding of no likelihood of confusion between "The Movie Buff's Movie Store" and "MovieBuff" when it placed the latter on the principal register despite West Coast's prior registration of "The Movie Buff's Movie Store."  Priority is accordingly to be determined on the basis of whether Brookfield used "MovieBuff" or West Coast used "moviebuff.com" first.

 B

West Coast argues that we are mixing apples and oranges when we compare its first use date of "moviebuff.com" with the first sale date of "MovieBuff" software.  West Coast reminds us that Brookfield uses the "MovieBuff" mark with both computer software and the provision of an Internet database;  according to West Coast, its use of "moviebuff.com" can cause confusion only with respect to the latter.  West Coast asserts that we should accordingly determine seniority by comparing West Coast's first use date of "moviebuff.com" not with when Brookfield first sold software, but with when it first offered its database online.

...

Brookfield first used "MovieBuff" on its Internet-based products and services in August 1997,  so West Coast can prevail only if it establishes first use earlier than that.  In the literal sense of the word, West Coast "used" the term "moviebuff.com" when it registered that domain address in February 1996.  Registration with Network Solutions, however, does not in itself constitute "use" for purposes of acquiring trademark priority. See Panavision, 141 F.3d at 1324-25.  The Lanham Act grants trademark protection only to marks that are used to identify and to distinguish goods or services in commerce--which typically occurs when a mark is used in conjunction with the actual sale of goods or services.  The purpose of a trademark is to help consumers identify the source, but a mark cannot serve a source- identifying function if the public has never seen the mark and thus is not meritorious of trademark protection until it is used in public in a manner that creates an association among consumers between the mark and the mark's owner.

...

 The district court, while recognizing that mere registration of a domain name was not sufficient to constitute commercial use for purposes of the Lanham Act, nevertheless held that registration of a domain name with the intent to use it commercially was sufficient to convey trademark rights.  This analysis, however, contradicts both the express statutory language and the case law which firmly establishes that trademark rights are not conveyed through mere intent to use a mark commercially...

 West Coast no longer disputes that its use--for purposes of the Lanham Act--of "moviebuff.com" did not commence until after February 1996.  It instead relies on the alternate argument that its rights vested when it began using "moviebuff.com" in e-mail correspondence with lawyers and customers sometime in mid-1996.  West Coast's argument is not without support in our case law--we have indeed held that trademark rights can vest even before any goods or services are actually sold if "the totality of [one's] prior actions, taken together, [can] establish a right to use the trademark."  New West, 595 F.2d at 1200.  Under New West, however, West Coast must establish that its e-mail correspondence constituted " '[u]se in a way sufficiently public to identify or distinguish the marked goods in an appropriate segment of the public mind as those of the adopter of the mark.' "  Id. ...

West Coast fails to meet this standard.  Its purported "use" is akin to putting one's mark "on a business office door sign, letterheads, architectural drawings, etc." or on a prototype displayed to a potential buyer, both of which have been held to be insufficient to establish trademark rights.  ...

 West Coast first announced its web site at "moviebuff.com" in a public and widespread manner in a press release of November 11, 1998, and thus it is not until at least that date that it first used the "moviebuff.com" mark for purposes of the Lanham Act.  Accordingly, West Coast's argument that it has seniority because it used "moviebuff.com" before Brookfield used "MovieBuff" as a service mark fails on its own terms.  West Coast's first use date was neither February 1996 when it registered its domain name with Network Solutions as the district court had concluded, nor April 1996 when it first used "moviebuff.com" in e-mail communications, but rather November 1998 when it first made a widespread and public announcement about the imminent launch of its web site.  Thus, West Coast's first use of "moviebuff.com" was preceded by Brookfield's first use of "MovieBuff" in conjunction with its online database, making Brookfield the senior user.

 For the foregoing reasons, we conclude that the district court erred in concluding that Brookfield failed to establish a likelihood of success on its claim of being the senior user.

V

 Establishing seniority, however, is only half the battle.  Brookfield must also show that the public is likely to be somehow confused about the source or sponsorship of West Coast's "moviebuff.com" web site--and somehow to associate that site with Brookfield.  See 15 U.S.C. § 1114(1);  1125(a). ...

"The core element of trademark infringement is the likelihood of confusion, i.e., whether the similarity of the marks is likely to confuse customers about the source of the products."  Official Airline Guides, 6 F.3d at 1391 ...  We look to the following factors for guidance in determining the likelihood of confusion:  similarity of the conflicting designations; relatedness or proximity of the two companies' products or services;  strength of Brookfield's mark;  marketing channels used;  degree of care likely to be exercised by purchasers in selecting goods;  West Coast's intent in selecting its mark;  evidence of actual confusion;  and likelihood of  expansion in product lines.  See Dr. Seuss Enters. v. Penguin Books USA, Inc., 109 F.3d 1394, 1404 (9th Cir.1997), petition for cert. dismissed by, 521 U.S. 1146, 118 S.Ct. 27, 138 L.Ed.2d 1057 (1997);  Sleekcraft, 599 F.2d at 348- 49;  see also Restatement (Third) of Unfair Competition §§ 20-23 (1995).  These eight factors are often referred to as the Sleekcraft factors.

A word of caution:  this eight-factor test for likelihood of confusion is pliant.  Some factors are much more important than others, and the relative importance of each individual factor will be case- specific.  Although some factors--such as the similarity of the marks and whether the two companies are direct competitors--will always be important, it is often possible to reach a conclusion with respect to likelihood of confusion after considering only a subset of the factors.  See Dreamwerks Prod. Group v. SKG Studio, 142 F.3d 1127, 1130-32 (9th Cir.1998).  Moreover, the foregoing list does not purport to be exhaustive, and non-listed variables may often be quite important.  We must be acutely aware of excessive rigidity when applying the law in the Internet context;  emerging technologies require a flexible approach.

A
We begin by comparing the allegedly infringing mark to the federally registered mark. [FN16]  The similarity of the marks will always be an important factor.  Where the two marks are entirely dissimilar, there is no likelihood of confusion.  "Pepsi" does not infringe Coca-Cola's "Coke." Nothing further need be said.  Even where there is precise identity of a complainant's and an alleged infringer's mark, there may be no consumer confusion--and thus no trademark infringement--if the alleged infringer is in a different geographic area or in a wholly different industry.  ...

 In the present case, the district court found West Coast's domain name  "moviebuff.com" to be quite different than Brookfield's domain name "moviebuffonline.com." Comparison of domain names, however, is irrelevant as a matter of law, since the Lanham Act requires that the allegedly infringing mark be compared with the claimant's trademark, see 15 U.S.C. § 1114(1), 1125(a), which here is "MovieBuff," not "moviebuffonline.com." Properly framed, it is readily apparent that West Coast's allegedly infringing mark is essentially identical to Brookfield's mark "MovieBuff."  In terms of appearance, there are differences in capitalization and the addition of ".com" in West Coast's complete domain name, but these differences are inconsequential in light of the fact that Web addresses are not caps-sensitive and that the ".com" top-level domain signifies the site's commercial nature.

 ...The domain name is more than a mere address:  like trademarks, second-level domain names communicate information as to source.  As we explained in Part II, many Web users are likely to associate "moviebuff.com" with the trademark "MovieBuff," thinking that it is operated by the company that makes "MovieBuff" products and services.  Courts, in fact, have routinely concluded that marks were essentially identical in similar contexts. ...
 

 The similarity of marks alone, as we have explained, does not necessarily lead to consumer confusion.  Accordingly, we must proceed to consider the relatedness of the products and services offered.  Related goods are generally more likely than unrelated goods to confuse the public as to the producers of the goods.  See Official Airline Guides, 6 F.3d at 1392 (citing Sleekcraft, 599 F.2d at 350).  In light of the virtual identity of marks, if they were used with identical products or services likelihood of confusion would follow as a matter of course.  ...

 The district court classified West Coast and Brookfield as non- competitors largely on the basis that Brookfield is primarily an information provider while West Coast primarily rents and sells videotapes.  It noted that West Coast's web site is used more by the somewhat curious video consumer who wants general movie information, while entertainment industry professionals, aspiring entertainment executives and professionals, and highly focused moviegoers are more likely to need or to want the more detailed information provided by "MovieBuff."  This analysis, however, overemphasizes differences in principal lines of business, as we have previously instructed that "the relatedness of each company's prime directive isn't relevant."  Dreamwerks, 142 F.3d at 1131.  Instead, the focus is on whether the consuming public is likely somehow to associate West Coast's products with Brookfield.  See id. Here, both companies offer products and services relating to the entertainment industry generally, and their principal lines of business both relate to movies specifically...Thus, Brookfield and West Coast are not properly characterized as non-competitors.  See American Int'l Group, Inc. v. American Int'l Bank, 926 F.2d 829, 832 (9th Cir.1991)...

Not only are they not non-competitors, the competitive proximity of their products is actually quite high.  Just as Brookfield's "MovieBuff" is a searchable database with detailed information on films, West Coast's web site features a similar searchable database, which Brookfield points out is licensed from a direct competitor of Brookfield.  Undeniably then, the products are used for similar purposes.  ...  The relatedness is further evidenced by the fact that the two companies compete for the patronage of an overlapping audience.  The use of similar marks to offer similar products accordingly weighs heavily in favor of likelihood of confusion.  See Sleekcraft, 599 F.2d at 348 ...

 In addition to the relatedness of products, West Coast and Brookfield both utilize the Web as a marketing and advertising facility, a factor that courts have consistently recognized as exacerbating the likelihood of confusion.  See, e.g., Public Serv. Co., 36 F.Supp.2d at 439;  Washington Speakers Bureau, Inc. v. Leading Authorities, Inc., 33 F.Supp.2d 488, 499 (E.D.Va.1999);  Jews for Jesus v. Brodsky, 993 F.Supp. 282, 304-05 (D.N.J.1998), aff'd, 159 F.3d 1351 (3d Cir.1998);  Interstellar Starship Servs., 983 F.Supp. at 1336;  Planned Parenthood Fed'n of America, 1997 WL 133313, at *8. Both companies, apparently recognizing the rapidly growing importance of Web commerce, are maneuvering to attract customers via the Web. Not only do they compete for the patronage of an overlapping audience on the Web, both "MovieBuff" and "moviebuff.com" are utilized in conjunction with Web- based products.

 Given the virtual identity of "moviebuff.com" and "MovieBuff," the relatedness of the products and services accompanied by those marks, and the companies' simultaneous use of the Web as a marketing and advertising tool, many forms of consumer confusion are likely to result.  People surfing the Web for information on "MovieBuff" may confuse "MovieBuff" with the searchable entertainment database at "moviebuff.com" and simply assume that they have reached Brookfield's web site.  See, e.g., Cardservice Int'l, 950 F.Supp. at 741.  In the Internet context, in particular, entering a web site takes little effort--usually one click from a linked site or a search engine's list;  thus, Web surfers are more likely to be confused as to the ownership of a web site than traditional patrons of a brick-and-mortar store would be of a store's ownership.  Alternatively, they may incorrectly believe that West Coast licensed "MovieBuff" from Brookfield ...Other consumers may simply believe that West Coast bought out Brookfield or that they are related companies.

 Yet other forms of confusion are likely to ensue.  Consumers may wrongly assume that the "MovieBuff" database they were searching for is no longer offered, having been replaced by West Coast's entertainment database, and thus simply use the services at West Coast's web site.  See, e.g., Cardservice Int'l, 950 F.Supp. at 741.  And even where people realize, immediately upon accessing "moviebuff.com," that they have reached a site operated by West Coast and wholly unrelated to Brookfield, West Coast will still have gained a customer by appropriating the goodwill that Brookfield has developed in its "MovieBuff" mark.  A consumer who was originally looking for Brookfield's products or services may be perfectly content with West Coast's database (especially as it is offered free of charge);  but he reached West Coast's site because of its use of Brookfield's mark as its second-level domain name, which is a misappropriation of Brookfield's goodwill by West Coast.  See infra Part V.B.

 The district court apparently assumed that likelihood of confusion exists only when consumers are confused as to the source of a product they actually purchase.  It is, however, well established that the Lanham Act protects against the many other forms of confusion that we have outlined.  See Pebble Beach, 155 F.3d at 544;  * Indianapolis Colts, 34 F.3d at 415-16;  Fuji Photo Film, 754 F.2d at 596;  HMH Pub. Co. v. Brincat, 504 F.2d 713, 716-17 & n.7 (9th Cir.1974);  Fleischmann Distilling, 314 F.2d at 155.

 The factors that we have considered so far--the similarity of marks, the relatedness of product offerings, and the overlap in marketing and advertising channels--lead us to the tentative conclusion that Brookfield has made a strong showing of likelihood of confusion.  Because it is possible that the remaining factors will tip the scale back the other way if they weigh strongly enough in West Coast's favor, we consider the remaining likelihood of confusion factors, beginning with the strength of Brookfield's mark.  The stronger a mark--meaning the more likely it is to be remembered and associated in the public mind with the mark's owner--the greater the protection it is accorded by the trademark laws.  ...

Although "MovieBuff" falls within the weak side of the strength spectrum, the mark is not so flabby as to compel a finding of no likelihood of confusion in light of the other factors that we have considered. Importantly, Brookfield's trademark is not descriptive because it does not describe either the software product or its purpose.  Instead, it is suggestive--and thus strong enough to warrant trademark protection--because it requires a mental leap from the mark to the product.  ...

 We thus turn to intent.  "The law has long been established that if an infringer 'adopts his designation with the intent of deriving benefit from the reputation of the trade-mark or trade name, its intent may be sufficient to justify the inference that there are confusing similarities.' "  Pacific Telesis v. International Telesis Comms., 994 F.2d 1364, 1369 (9th Cir.1993) (quoting Restatement of Torts, § 729, Comment on Clause (b)f (1938)).  An inference of confusion has similarly been deemed appropriate where a mark is adopted with the intent to deceive the public.  See Gallo, 967 F.2d at 1293 (citing Sleekcraft, 599 F.2d at 354).  The district court found that the intent factor favored West Coast because it did not adopt the "moviebuff.com" mark with the specific purpose of infringing Brookfield's trademark.  The intent prong, however, is not so narrowly confined.

 This factor favors the plaintiff where the alleged infringer adopted his mark with knowledge, actual or constructive, that it was another's trademark.  ...  In the Internet context, in particular, courts have appropriately recognized that the intentional registration of a domain name knowing that the second-level domain is another company's valuable trademark weighs in favor of likelihood of confusion.  See, e.g., Washington Speakers, 33 F.Supp.2d 488, 500.  There is, however, no evidence in the record that West Coast registered "moviebuff.com" with the principal intent of confusing consumers. Brookfield correctly points out that, by the time West Coast launched its web site, it did know of Brookfield's claim to rights in the trademark "MovieBuff."  But when it registered the domain name with Network Solutions, West Coast did not know of Brookfield's rights in "MovieBuff" (at least Brookfield has not established that it did).  Although Brookfield asserts that West Coast could easily have launched its web site at its alternate domain address, "westcoastvideo.com," thereby avoiding the infringement problem, West Coast claims that it had already invested considerable sums in developing its "moviebuff.com" web site by the time that Brookfield informed it of its rights in the trademark.  Considered as a whole, this factor appears indeterminate.

Importantly, an intent to confuse consumers is not required for a finding of trademark infringement.  ...  Instead, this factor is only relevant to the extent that it bears upon the likelihood that consumers will be confused by the alleged infringer's mark (or to the extent that a court wishes to consider it as an equitable consideration).  See Sleekcraft Boats, 599 F.2d at 348 n. 10. Here, West Coast's intent does not appear to bear upon the likelihood of confusion because it did not act with such an intent from which it is appropriate to infer consumer confusion.

 The final three Sleekcraft factors--evidence of actual confusion, likelihood of expansion in product lines, and purchaser care--do not affect our ultimate conclusion regarding the likelihood of confusion.  The first two factors do not merit extensive comment.  Actual confusion is not relevant because Brookfield filed suit before West Coast began actively using the "moviebuff.com" mark and thus never had the opportunity to collect information on actual confusion.  The likelihood of expansion in product lines factor is relatively unimportant where two companies already compete to a significant extent.  See Official Airline Guides, 6 F.3d at 1394.  In any case, it is neither exceedingly likely nor unlikely that West Coast will enter more directly into Brookfield's principal market, or vice versa.

 Although the district court did not discuss the degree of care likely to be exercised by purchasers of the products in question, we think that this issue deserves some consideration.  ...

 The complexity in this case arises because we must consider both entertainment professionals, who probably will take the time and effort to find the specific product they want, and movie devotees, who will be more easily confused as to the source of the database offered at West Coast's web site.  In addition, West Coast's site is likely to be visited by many casual movie watchers.  The entertainment professional, movie devotee, and casual watcher are likely to exercise high, little, and very little care, respectively.  Who is the reasonably prudent consumer?  ... We need not, however, decide this question now because the purchaser confusion factor, even considered in the light most favorable to West Coast, is not sufficient to overcome the likelihood of confusion strongly established by the other factors we have analyzed.

In light of the foregoing analysis, we conclude that Brookfield has demonstrated a likelihood of success on its claim that West Coast's use of "moviebuff.com" violates the Lanham Act. We are fully aware that although the question of "[w]hether confusion is likely is a factual determination woven into the law," we nevertheless must review only for clear error the district court's conclusion that the evidence of likelihood of confusion in this case was slim.  See Levi Strauss & Co. v. Blue Bell, Inc., 778 F.2d 1352, 1356 (9th Cir.1985) (en banc).  Here, however, we are "left with the definite and firm conviction that a mistake has been made."  Pacific Telesis Group v. International Telesis Comms., 994 F.2d 1364, 1367 (9th Cir.1993).

...

VI

 Having concluded that Brookfield has established a likelihood of success on the merits of its trademark infringement claim, we analyze the other requirement for preliminary injunctive relief inquiry, irreparable injury. Although the district court did not address this issue, irreparable injury may be presumed from a showing of likelihood of success on the merits of a trademark infringement claim.  See Metro Pub., Ltd. v. San Jose Mercury News, 987 F.2d 637, 640 (9th Cir.1993) ("Once the plaintiff has demonstrated a likelihood of confusion, it is ordinarily presumed that the plaintiff will suffer irreparable harm if injunctive relief is not granted.").  Preliminary injunctive relief is appropriate here to prevent irreparable injury to Brookfield's interests in its trademark "MovieBuff" and to promote the public interest in protecting trademarks generally as well.

VII

 As we have seen, registration of a domain name for a Web site does not trump long-established principles of trademark law.  When a firm uses a competitor's trademark in the domain name of its web site, users are likely to be confused as to its source or sponsorship.  Similarly, using a competitor's trademark in the metatags of such web site is likely to cause what we have described as initial interest confusion.  These forms of confusion are exactly what the trademark laws are designed to prevent.

 Accordingly, we reverse and remand this case to the district court with instructions to enter a preliminary injunction in favor of Brookfield in accordance with this opinion.

 REVERSED and REMANDED.