The blog Only a Game had a wonderful post recently about the issue with Wikipedia, which is not about the information that is in many of the articles, but about what can be known to be behind them, and thus the confidence that one should or should not place in them. Here is a quote:
The Wikipedia knows nothing, or rather, someone using the Wikipedia cannot know anything from that alone. Whoever refers to a topic on the Wikipedia cannot be said to possess justified true beliefs (i.e. knowledge, conventionally construed), because no-one who edits the Wikipedia has been credibly selected for expertise, creating a gap in justification. Wikipedia editors have self-selected based on personal interest – which is why there are so many articles about (say) Star Trek and videogames. This process could still convey expertise – it frequently does about as well as any other encyclopaedia! – but we are never certain that it has done so in a subject we ourselves know nothing about. Even when Wikipedia provides correct information we cannot know it has done so, and thus can possess no justification for claiming that we do. I say this as someone who uses and even edits the Wikipedia on a regular basis, and who appreciates its remarkable virtue as a public database. It is not that particular resource that I am questioning, but the very idea of databases as a means of knowing. Kn0wledge, whatever it might be, becomes tainted with doubts when it is compiled using the kinds of techniques that lie behind the Wikipedia – and this in turn raises interesting questions about all our knowledge.