Universal Edit Button for Wikis etc.
This is a cool idea to bring the concept of the user-writable web a bit more into the mainstream. A microformat for Wikis and similar sites to let a Firefox 3 plugin know that a site is editable.
Now I really will have to pick up development on my Wiki implementation, Friki. Adding this feature is actually a trivial page template change, but I want to make a new version anyway.
The uniquely flexiblele page transformation approach taken by Friki makes it easy to change the markup syntax to support WikiCreole, too.