A wiki is a server program that allows users to collaborate in forming the content of a Web site. Wiki allows anyone to edit, delete or modify content that has been placed on the Web site using a browser interface, including other users' contributions.
Wikis are known as the tool of choice for large, multiple-participant projects. Visitors can also create new content and change the organization of existing content. The prime example of a wiki in action is Wikipedia, the open source encyclopedia. Wikipedia builds on transparency, simple linking, and a lot of people being involved in editing and authoring.