Last week, a bunch of important people from Washington, D.C. packed their bags and flew to California to meet with a bunch of important people from Silicon Valley. The occasion was not the usual fundraising dinners or donor-wooing — it was a terrorism summit. Government types are freaked out about the role of technology in how groups like ISIS recruit members and plan attacks. They think the heads of tech companies like Facebook, Apple, Twitter, and Google can do more to help them keep the world safe.