I've talked with students a lot about their use of Wikipedia. I've had some concerns with using the online encyclopedia as users can post any information they like to the entries. Media often cite Wikipedia as a source, yet have they fact-checked the information?
Sure enough, a college student in Ireland posted a fake quote to an entry about French composer Maurice Jarre as part of "an experiment." Sure enough, several UK media took the bait and published the fake quote as part of Jarre's obituary.
Steve Walling has built a great slideshow instructing journalists on how to use Wikipedia. I really like this piece of advice he offers: "WikiPedia should be the first place you look for information, not the last ... it should help you form questions for your story, not give you the answers."