http://education.yahoo.com/reference/encyclopedia/

It seems Britannica has licensed its free content to Yahoo.

This makes it all the more important that we set up a review mechanism for Wikipedia. If we could boast 25,000 peer reviewed *complete* articles, Yahoo would very likely use our content for free rather than pay for Britannica's. (Or, at least, they would list both--and we'd get loads of traffic.)

Larry