Wikipedia

Wikipedia is the most visited wiki by far. Founded in 2001 by Jimbo and Larry Sanger, it has also become the most expansive wiki. The site was initially developed along with Nupedia.

The site was initially open to all visitors and users. However, as time passed by, the vandalism started to increase at such a rapid rate that pages started to get semi-locked to prevent this vandalism from spreading.

Due to the openness and lack of fact-checking throughout the site, many people have criticized the wiki, including Larry Sanger.