Wiki

A WiKi is a collaborative website which can be directly edited by anyone with access to it.

A full description on WiKi can be found by clicking the paragraph excerpt below...

A wiki is software that allows users to create, edit, and link web pages easily. Wikis are often used to create collaborative websites...

Book:

The Wiki Way: Quick Collaboration on the Web
by Bo Leuf (Author), Ward Cunningham (Author)

Available at Amazon.com