SwikiSwikis, or "CoWebs", are a simple system which allow multiple people in remote locations to edit a centralized collection of web pages. Here's how it works.
Each page in the system is a regular web page. To modify a page, click the "Edit this page" link at the top or bottom of that page–a new page will come up that allows you to edit the pages. The syntax used in editting a page is a simplification of HTML described at Formatting Rules.
There is a Sandbox new users can experiment in.
The Swiki system was developped by Mark Guzdial at Georgia Tech; more information is available at http://pbl.cc.gatech.edu:8080/myswiki.1.