The Wikipedia is one of those simple and yet enormously successful ideas (like the world wide web itself). The English Wikipedia, begun in 2001, currently has 1,223,328 articles. A recent study by Nature found that it had only slightly more errors than the Encyclopaedia Brittanica in articles relating to the natural sciences.
Anyone can edit articles in the Wikipedia. The worldwide collaborative effort is a model of what can be achieved without regulation. The article About Wikipedia is a good place to find out more.
Yesterday, I was looking at various articles about the Wikipedia itself and other "wikis" with a view to using the model for some collaborative editing. In the course of my browsing, I was amused and delighted to find that there is a Latin Vicipaedia. If you've finished today's crossword puzzle and Sudoku, and feel in need something more challenging, try the article on string theory in Latin: Theoria Chordarum.