Let's say you've created a program or launched an open source project, and now you have people's attention. They start to ask more and more questions, taking more and more of your precious developer time to answer. They fill your mailbox, sometimes even spam your IRC channel, often repeating the same questions. You know that you need to provide something in writing to help your users. But where should you start? What tools can you use? What output format do you choose? What subjects must you cover?