In my experience, Wikipedia is often a good resource, especially for pop culture and computer tech terms. But since it is a fully community-operated enterprise, there are some pratfalls about relying on it for information, especially since some organizations use it as a marketing tool for themselves, attempting to control entries they're interested in.
This type of cybersquatting is quite widespread but up until now, difficult to track. That's changed however, with the creation of Wikiscanner, a search engine that allows you to see what organizations have been editing Wikipedia. You can, for instance, look up to see what Wikipedia users from different political groups, business, churches, and any other organization have been up to on the site. Early results are showing that many employees seem to have a habit of editing the entries of their own company/organization. You can also see that at least one person at the New York Times deliberately defaced Wikipedia's entry for George W. Bush with the words "jerk" inserted into the page repeatedly.
It's not completely foolproof, however, since Wikipedia only reveals your IP address if you edit a page without signing up for an account. Still, the data is interesting. Wikiscanner is being deluged with huge amounts of traffic right now but when things calm down, it should prove to be a very interesting research tool for us here at NB and for everyone in the blogosphere.