Wikis

Wikis were created by Ward Cunningham, and are a collection of webpages designed so that people with access can modify or contribute to the content. They are used for collaborative websites (like Wikipedia). It can be expanded to "What I Know Is" but that is a backronym (not actually meant to be an acronym). The first wikis appeared in the mid-1990s, because scientists and engineers used them as dynamic knowledge bases. I think reliabiliity is an opinion, some downsides are people can change others posts, and many teachers tell their students that Wikipedia is not a reliable source. I tend to use Wikipedia a lot, mostly because of convenience, and its a site with so much information about tons of topics. Some info might not be valid if the poster is not an expert in the field he is commenting on, but at least all sources are cited, so if youre really THAT worried about it you can check.

sources: Wikipedia, http://net.educause.edu/ir/library/pdf/ELI7004.pdf