Valve Developer Wiki
Via Gamasutra, the news that Valve has opened a Developer Community Wiki. From the post: "The system is intended to be a pool of knowledge that mod authors can contribute to, as well as consult for advice on how to use the robust Source engine. The Community is built using MediaWiki, an open-source GNU tool for allowing entries and posts to be edited and refined by anyone with an account. The same technology powers the popular Wikipedia, an online encyclopedia."
The wiki is a good tool for collaboration. It's encouraging to see Valve step in with an official one. The flip side is that maybe they'll be reluctant to share any details that reverse-engineer too deeply. Here's a similar wiki for Battlefield 2, that focuses on the python code and it's largely unpublished interface. Because it enjoys independence from EA and DICE, the folks there are digging up pleanty of undocumented details.
Wiki has a lot of moderation throught the way it was designed. Anyone can contribute, anyone can commit vandalisme and anyone can undo vandalisme (it has an undo button in a sense). I contribute regulary to wikibooks and vandalisme turns up once in a while and is fixed practicly immediatly. Till now it hasn't been much of an issue. Ofcourse I'm not going to post a link to any book I contribute too as a large number of people vandalising the same page after each other can be a problem.