At the same time, I became interested in the DOAP project, and decided that with a little bit of help from Joel, I could do something along the lines of what he's doing, only much simpler: Simply provide an image that lights up when a page contains DOAP information, and allow the image to be clickable to redirect to an HTML description of the project.
The project is pretty well described at that page, and is really simple: if a page supports DOAP (with a <link> tag), then it will light up. Click the little icon, and all of a sudden, you're viewing all the information about the project: mailing list, CVS, Maintainer info, etc.
The page, for the time being, is in French only, and maintained by stork, who is now on vacation. However, the idea is something I hope to expand upon, and perhaps to integrate with other similar projects. There are already extensions which do information for CC licensed pages, and with the FOAF extension, these kind of things could be provided to offer a more generalized semantic web plugin.
Mostly, this is just me learning enough XUL+JS to learn how extensions work, and how to make one, but it's still pretty nifty. Fore more information on the extension, see the page.
Also, if anyone tries it out, and it works (you can tell how to tell if it works at that page), please, open Firefox's about page and copy paste me your version string. The same applies if it doesn't work. I have gotten one complaint that in XP SP 2 with the latest nightly build that it doesn't work. I am aware that it will likely only work with .9 and up, because it depends on the new extension manager. Of course, anyone on Windows should be running .92 anyway, as there is a vulnerability in versions less than that.
It's late. I'm tired. But I feel accomplished. And that's a good thing.