Most researchers and teachers (I am guilty of this one to an extent) would cite wikipedia as a holy grail of knowledge but one fact still remains: anyone can edit entries in wikipedia. The first entry I edited was a minor edit on the Ubuntu OS page of wikipedia, adding Lubuntu and its description. I am not saying that what I added was erroneous but we must not ignore the fact that it can be edited by anyone.
There are many entries in wikipedia.org that are unbalanced. Here's a good example from penny-arcade.com click here to view the example.
Search for Eli Soriano on wikipedia and you will see the constant changes to its entries by the supporters of Soriano and his 'enemies' in Inglesia In Cristo and other religious sects.
Wikipedia must be starting point of any research but it must not end there. Remember Validity and Reliability are the important factors to a research. If people would say they pick that data from wikipedia, that's as good as saying they got the information from a reliable rumor mill.
Always re-check with other encyclopedia based sites. Do not trust everything that you read in the internet.