After eighteen-year-old Michael Brown was shot and killed by a police officer in Ferguson, Missouri, Bergis Jules found himself worrying not only over the horrors of the present, but also over how little of the present was likely to be preserved for the future. The best reporting on the aftermath in Ferguson was being produced by activists on Twitter, a notoriously ephemeral medium. Jules, then an archivist at the University of California, Riverside, had the impulse to start saving tweets, but wasn’t sure how. “That whole weekend, watching things unfold, I thought, ‘This is a really amazing historical moment;…