“Imagine a world in which every single person on the planet is given free access to the sum of all human knowledge. That’s what we’re doing.” - Jimbo Wales in a Slashdot interview.
Wikipedia measures well against Britannica according to Nature.[1][2]
Recent count is 40,000 edits on 24,000 pages - and some of them haven't been reverted! (current count) I've also uploaded about 280 original images that are currently used in mainspace (most are now hosted on WP:Commons) and created 240 new articles so far (according to Escaladix' tool). My first edit: diff was not very good.