I updated the Scuttle firefox plugin to work with Firefox 4. This was the one utility that was holding me back from upgrading to Firefox 4. I created a "github repository.":https://github.com/underhilllabs/Scuttle-Plugin-Firefox-4 for the project. Feel free to fork the project. Its a good simple plugin if you'd like to learn how to write one.
The original scuttle firefox plugin hasn't been upgraded since 2007. The version in This updated version is compatible with Firefox 4. You can view the source or fork the project at "my github repository.":https://github.com/underhilllabs/Scuttle-Plugin-Firefox-4 or you can download the plugin directly: "scuttle-0.4.2-firefox+fl.xpi":https://github.com/downloads/underhilllabs/Scuttle-Plugin-Firefox-4/scuttle-0.4.2-firefox+fl.xpi
Scuttle is an open source "Website Bookmarking System":http://scuttle.org. I switched to it for my bookmarking needs after Yahoo! announced they were shutting down delicious.com. The cool thing about Scuttle is that its open source, (its written in PHP.) so you can download the source and run it on your own web server and if there's a new feature you want for your social bookmarking you can write it, also since it runs on your own server, you can be sure that the service will never end (just make regular backups.) The bad news is that you need to have a web server to run it. If you are just interested in an alternative to delicious you can try "pinboard.in":http://pinboard.in.
Credit for the original code goes to Marcus Campbell, developer of scuttle and the scuttle plugin and also to "Andreas Keller":http://akeller.eu/en/firefox-3-und-das-scuttle-add-on/ for originally updating the scuttle plugin for Firefox 3.