I mentioned to Tom recently that I had "gone to" a virtual seminar on using wikis as a collaborative tool and thought it could really come in handy in a number of situations. Since he didn't know what a wiki was, I explained it to him and introduced him to Wikipedia. This led to a discussion on how anyone could possibly rely on something as a reference tool when anyone could make changes to it. There has been a lot of online and media discussion about wikis recently (or maybe I've just become more aware of the discussion) and after the Steven Colbert bit on Comedy Central, wikis have become the topic in more places. Take a look at Michael Calore's blog and follow the links to the YouTube Colbert video and a response by a Wikipedia moderator:
For more on Wikipedia and how it is reviewed and updated take a look at their Help pages.