Wikipedia is the World’s biggest encyclopedia. Anyone can edit or contribute articles.
Articles are under GNU Free Documentation License.
As of now:
It has over 16,00,000 articles
12,00,000 visitors
It has editions in about 200 different languages
There are 26,000 contributors and most contributors are anonymous
There’s even a Marathi version:
http://mr.wikipedia.org/wiki/%E0%A4%AE%E0%A5%81%E0%A4%96%E0%A4%AA%E0%A5%83%E0%A4%B7%E0%A5%8D%E0%A4%A0
(that link may look like ass)