Zoho Wiki

Zoho Wiki is a free hosted wiki with WYSIWYG editor, versioning, sub pages, tags, dashboard, rss feeds and it is search engine friendly. With Zoho Wiki you can create groups and add, edit and share contents among them. Like all Zoho products it works like a charm so you have to check it out to see all it's features.

HiperLink: http://wiki.zoho.com/