Wikipedia reached its Millionth article yesterday, which is a damn impressive feat. The millionth article was on Jordanhill railway station.
Speaking to Wikinews, the site's founder Jimmy Wales said "We are thrilled that our millionth article in English is about the Jordanhill railway station. This is not something which would appear in a traditional encyclopedia, and it shows how Wikipedia reflects the needs and interests of people everywhere, and not just the dictates of what academics and cultural mavens claim is worthy of an encyclopedia."
The next largest Wikipedia is the German version, which contains over 350,000 articles. Currently there are Wikipedias in 125 different languages, containing 3.3 million articles in total.
The BBC's h2g2 site, also a community-built encyclopedia but with a different editing model, currently contains 7650 Edited Entries (see stats). That's perhaps not quite a fair comparison, as h2g2 also has a vast number of unedited articles. Wikipedia only has 904 'featured articles' (there's one on the home page every day), but the quality of unfeatured Wikipedia articles tends to be higher than unedited h2g2 articles.
Of course, they're different projects, with perhaps different aims (although I think Douglas Adams's original vision is perhaps now closer to Wikipedia than h2g2).
Anyhow, I'm rambling. Congratulations to Wikipedia! I hope this story gets some mainstream press coverage.