Our leading newspaper asked several university professors, the leading experts of their branch, to evaluate Wikipedia articles of their expertise. Only Finnish, if I recall correctly. The results weren't as bad as one could have suggested. They mostly criticized the lack of depth and neutrality, the facts being basically correct. That said, half a truth can work as a lie even more effectively than an alternative truth... A tool, as Arlo said. A tool that can lead to reliable sources for those who really want to know, a tool that can give a hint about what people are talking about. I've often used it for finding out who the people in the "N.N. passed away" threads here. American baseball stars aren't too famous here...
What concerns me more than Wikipedia is that people have moved from Google to Facebook to get information and answers. Finding a FB forum of like minded and asking for their advise can fortify any belief stronger than any algorithm based on previous history. Recently I read that here in Finland the vauva.fi ("baby.com", the BBS of a baby/mother magazine) has become a leading forum for all kinds of Q&A. The previous leader was suomi24.fi which started as a dating forum... Ask anything, you'll get answered anything!