Our digital lives are built on the promises of strangers. Promises about how technology will change your life, or who will maintain this code, or what will happen to your data. These promises are hard to keep: organizations have changes of heart or changes of fortune. Ninety percent of new organizations fail. Eighty percent of open-source software projects are unsuccessful. When projects and organizations fail, the technology that we rely on may change, or be abandoned, or disappear entirely. This talk covers what we can do about it. Keith Porcaro, fellow at Harvard's Berkman Klein Center, presents his work on data trusts, a legal tool for governing and protecting digital movements.