"Who Knows?": Excellent article on Wikipedia and how it works. One interesting tidbit:

To put Wikipedia's achievements in numerical context, at the same time it was celebrating the publishing of its one millionth entry (a Hebrew article on the Kazakhstan flag) in less than four years, the Oxford Dictionary of National Biography launched its latest edition. It had taken 12 years to complete, yet contained a comparatively tiddly 55,000 biographies. It also cost some £25m to create. Wikipedia has so far been bankrolled by Wales, but the total cost so far is still around £300,000.

The current Encyclopedia Britannica has 44m words of text. Wikipedia already has more than 250m words in it. Britannica's most recent edition has 65,000 entries in print and 75,000 entries online. Wikipedia's English site has some 360,000 entries and is growing every day.

Just for reference, £1 UK = $1.85 US. (Via LinkMachineGo.)