So You Want a Wiki
From Library Success: A Best Practices Wiki
So You Want To Build a Wiki: Important Considerations
Where Will Your Wiki Live?
DIY Wikis (hosted on your server, installed by you)
Check out the Wiki Matrix to compare wikis side-by-side.
Hosted Wikis/Wiki Farms (your wiki on another company's servers)
- PBWiki (free)
- Schtuff (free)
- SeedWiki (free)
- Wikispaces (free)
- JotSpot, ceases on January 15th, 2009, migrating to Google sites
- SocialText (enterprise wiki)
- Netcipia (free and enterprise wiki)
- Wetpaint (free but can upgrade to remove ads)
Check out the List of wiki farms in the Wikipedia.