Wow. I still remember the days when people steered clear of Wikipedia because it was inaccurate. Well, it still may not be perfectly accurate, but it blows every other encyclopedia away with sheer volume of content.
2 million articles. For quick reference, Encyclopedia Britannica boasts 120,000 articles in its online version.
But, it’s not only about the volume; you go to Wikipedia because no other encyclopedia can even think about adding insanely detailed data about the light saber from Star Wars or obscure Nintendo DS games. Wikipedia, simply put, owns every other encyclopedia out there, and I don’t see this situation changing ever again.
[via]
It has even more than that if you count the non-english versions too.
Aside from being a good encyclopedia, its also a good source of foreign language reading material. Reading random articles from ja.wikipedia.org has helped my Japanese learning immensely.