Every year, Mozilla runs a contest called Extend Firefox, which is designed to name the best Firefox extensions created in the previous 12 months. This year’s list of winners is out, and one of the winners was previously written up here a while back: Pencil.
In his writeup, Mike noted that Pencil works by marrying Firefox’s Gecko drawing engine with the ability to display, save and load an external canvas with a palette of shapes. You end up with a capable drawing program right in your browser.
I use Pencil, and fans of visualization tools like Visio will especially get a kick out of it. Author Duong Thanh An won a grand prize from Mozilla for it.
The second Firefox extension on Mozilla’s list this year is Tagmarks, produced by Felipe Tassario Gomes. I have this on my list to try. It adds a set of icons to Firefox’s quick bookmarks, allowing you to quickly add tags to your bookmarks by clicking on each icon. You can find screenshots at the download page linked to above.
The third grand prize winner this year is also a bookmarks soup-up extension: HandyTag. This one comes from Rémi Szymkowiak It provides a set of the most relevant keywords in the bookmark’s edition panel. The keywords are retrieved from many different sources.
For many more useful Firefox extensions see OStatic’s roundup of open source educational resources here (the Firefox Superguide at the top includes a slew of good extensions).