When I set out with my collaborator Eric Fleegler, MD, MPH, to build a web-based tracking system for children with attention deficit hyperactivity disorder (ADHD), we focused on a single problem—getting parents and teachers to fill out symptom questionnaires in time to help doctors make informed clinical decisions at follow-up visits. We had no inkling of the possibilities that this kind of software platform could hold, or how it might grow in the future. …