Wiki is a socially edited database source for information. As socially edited database, some, if not much, of what's written is suspect. As a main source for information, people ought to look elsewhere.

Here's a great article that supports my thesis: "Wikipedia is gaining an increasingly bad reputation in schools all over the world. Teachers will argue that Wikipedia is not a reliable source with credibility to be cited in a formal essay or term paper. Teachers believe that due to the multitude of anonymous updates, there is not enough reliable information to base ideas upon. Even if Wikipedia can detect obvious errors such as in the Einstein page case (mentioned earlier), there is no way that it can monitor every single error. "

"In my opinion, Wikipedia is acceptable to a certain extent. I do not believe that it is a “scholarly” source of information in context. There are many sources on the Internet with much more reliable information."

http://itgsonline.com/?p=224

And this rather sums it all up nicely: http://library.williams.edu/citing/wikipedia.php