I find Wikipedia very helpful for quick contact information.  If someone mentions “the world’s smallest country, Sealand, is for sale,” and I want an idea of what Sealand is, Wikipedia is a good place to get a rough idea of what is going on.  As far as I’ve seen, the major usage of Wikipedia is this kind of quick and dirty info dump by people who just want to get a basic idea of something and are aware that some of the information may be false.  The Wiki user base is (I think) pretty savvy as a whole are also pretty good at smelling fake info (if an entry begins “<insert celebrity name> is a famous child molester…”, you can’t trust it).  The idea of citing it in law school is ludicrous (see the Wiki site disclaimer), and it should not be allowed as a primary reference in school research, but there is definite value in using it in school as a secondary source, not the least reason for which is that it teaches the valuable lesson that all information, even that from “legitimate” sources, is suspect, and you have to do some legwork to find out the real story.  The entries often hare extensive primary source notations that anyone can follow-up on.  And, although false information and vandalism occurs, the overall reliability (accuracy and completeness) is better than that of asking a friend, posing the question on a message board, doing an online search, or even turning to media informational outlets.  Suspect articles get marked, and additional disclaimers appear at the top of articles needing sourcing or other improvement.  The knowledge base is not perfect, but the thing is just too damn useful to dismiss out of hand.

The bits that no-one really cares about (you know, the academic bits!) are usually accurate and interestingly written.

When wikipedia decides that John Byrne is not worthy of inclusion on their site, then I'll agree that wikipedia is not worthy of acknowledgement here.

Wikipedia is a good concept, marred by the fact that there are too many idiots on the Internet.