Middlebury College banned it, but 46% of college students and 50% of college grads use it.
Twelve year olds point out errors in its competition, while those over 50 are among its smallest demographic — just 29% (Just! 29%!) say they’ve used it.
It’s Wikipedia, of course, and the numbers come from a recent Pew Internet Project memo reporting that Wikipedia is used by 36% of the online population and is one of the top ten destinations on the web.