I recently decided to start a personal Wiki. I decided to do this, partially, not only because wanted to mess around with Github, but more importantly, because I often find myself spending a lot of time figuring things out only to forgot the issue a year later when having the same problem.
I highly recommend the use of a Wiki (Trac, Redmine, Github, etc.) for any software team. I’ve found them to be excellent tools of collaboration. My personal Wiki, so far, is pretty small. I’ve only been using it for a month or so. Even so, I’ve already referred to it a number of times. I wish I had been maintaining a personal development wiki throughout my career!