I use Wikipedia when I don't care all that much about how accurate the information might be. On the whole, the information in Wikipedia tends to be more extensive and in depth than, say, encyclopedias, but it falls prey to the problem that any one entry you look up could have been a) written by well intentioned person who doesn't quite have the facts straight (which hasn't been caught by the community yet) or b) deliberately sabotaged. Unfortunately, there is no way to disprove either of these possibilities without further research.