Every page on Wikipedia has an accompanying ‘Talk’ page, where people discuss the main article and propose changes to it. Having a look at some of the talk pages is informative because it really shows off the lack of expertise among the people who are working on these articles. Much as I enjoy and admire Wikipedia as an effort, seeing things like the discussion on ‘tar sands’ makes me wonder how trustworthy the site is as a source of information. Often, the arguments on talk pages seem to be superficial and unsupported by evidence or strong argumentation.
As with everything else, we need to try to retain healthy skepticism about new information without becoming dogmatic about what we already believe. That is a tough thing to accomplish – especially given the scope and complexity of issues affecting us all.