Wikipedia, the the free encyclopedia that anyone can edit has been coming up in the world. I've noticed lots of citing of Wiki lately, and this is not a good thing.
I assume that the citers just don't realize that Wiki is the world's graffitti book. Until recently anybody could add an entry to Wiki, and right up to the present, anybody can edit. The theory is that errors will eventually be corrected, but the key word is eventually. Articles are not checked before being entered into Wikipedia, so there is no reason to trust anything in a Wiki article.
I recently edited the Wiki article on Huckleberry Finn because it claimed that the Duke and the King were trying to swindle four orphan girls, when in fact it was 3 orphan girls. This is a minor plot point, but if you've read the book it's hard to get that wrong because the girls are described rather vividly:
It's a pretty long journey. But it'll be lovely; wisht I was a-going. Is Mary Jane the oldest? How old is the others?"
"Mary Jane's nineteen, Susan's fifteen, and Joanna's about fourteen -- that's the one that gives herself to good works and has a hare-lip."
Lately there's been a new development. Other organizations, such as answers.com and reference.com take articles from Wiki and present them as valid resource citation materials. They do mention Wiki, but if you don't know about Wikipedia, and don't check it out, you have no idea your source is not verified before it is placed online. What's worse, when you make corrections to the Wiki article, the corrections are not carried over to those other web sites. So they have all the problems of Wikipedia and none of the benefits.
Wiki is a convenient place to start researching a subject, but do not use it as a primary source - follow links from the Wiki article to verified, vetted sources.
UPDATE: the moron who is suing me for doing a production of my own play cited Wikipedia in a court document to bolster his argument that because he made one aborted attempt to direct my play, he therefore owns a copyright on all subsequent performances. He is both an artistic AND a legal idiot. So I updated the item he cited, the Wikipedia entry for "stage picture." The last line is my little howdy to the cretin.