Wikipedia is useful. Just remember that this is a site that can be edited by anyone, yes anyone. That means that it is not an accurate site. If that is the case, then what good is it to a writer or researcher?
The answer is that it is an extremely useful tool provided you remember the nature of the site.
For me and other writers it is a fantastic starting point for ideas and as a pointer to other sources of information. It always gives me a good overview of a topic. Then I go from there to other sources to confirm facts or to find more reliable sources. I take the key info from Wikipedia about the subject and list them in point form. From there I either disprove, confirm, or add more facts from other sources. As a starting point though I find Wikipedia invaluable.
Wikipedia is NOT an reliable, accurate source. Remember this and then use it as just another tool. Good journalists always confirm facts with multiple sources wherever possible. The same holds true here. For me it is a powerful tool to uncover ideas. I just have to remember to use the complete toolbox to write the articles that are sometimes inspired by my Wikipedia searches.