Cultivate an attitude of skepticism when it comes to web-based content. If you have any doubt whatsoever about the reliability of any given website, clear it with your instructor or check with a librarian before you use it in your paper.
Here is what Wikipedia itself has to say about using Wikipedia for academic research:
".... citation of Wikipedia in research papers may be considered unacceptable, because Wikipedia is not considered a credible or authoritative source. This is especially true considering anyone can edit the information given at any time.
Follow two simple rules:
1) Do your research properly. Remember that any encyclopedia is a starting point for research, not an ending point.
2) Use your judgment. Remember that all sources have to be evaluated."
For more on what Wikipedia says about Wikipedia and academic research, see:
You may also want to use the new Cite Unseen widget, which scrolls through citations in Wikipedia articles and inserts icons denoting the type/reliability of each source listed.
Take a look at some of these great website evaluation tips!