Andrea Gohr is trying trying to put some momentum behind the Universal Edit Button extension for Firefox. As Gohr puts it,
The idea is simple: whenever you are on an editable website (usually a wiki), your borwser should display an icon just like it does when you’re on a website with an RSS feed.
Gohr stepped in and took the existing FF addon for this and fixed some bugs and other issues and it is now in the experimental repository. Gohr is hoping enough people will check it out and review it to have it moved to the regular Firefox Extension area.