Any collaborative website that users can easily modify via the web, typically without restriction. A wiki allows anyone, using a web browser, to edit, delete or modify content that has been placed on the site, including the work of other authors. This has been found to work surprisingly well since contributors tend to be more numerous and persistent than vandals and old versions of pages are always available.
Text is entered using a simple mark-up language which is then rendered as HTML. A feature common to many of the different implementations is that any word in mixed case LikeThis is automatically turned into a link to a page of that name, which may or may not exist (similar to the linking in this dictionary).
In contrast, a web log, typically authored by an individual, does not allow visitors to change the original posted material, only add comments.
Wiki wiki means "quick" in Hawaiian. The first wiki was created by Ward Cunningham in 1995.