I find myself using Wikipedia more and more these days. And linking to it as well. Apparently I'm not the only one when looking at these research results. Increasingly I'm using Wikipedia directly however, not through a search engine. So it will be interesting to see how, and if, Google and Yahoo will embrace that trend(?).
"In a research project, Cuhalev gathered a random sample of about 1,000 of the 1.4 million topics covered by Wikipedia. He then ran the terms through the Google, Yahoo, and MSN search engines. He found that Wikipedia did in fact appear with remarkable consistency in the upper reaches of search results. On average, the online encyclopedia appeared in the top-ten search results 65% of the time - and 26% of the time it actually had two results in the top ten. (Cuhalev has posted a summary of his findings on his blog, and the full report can be downloaded here.)"