The contest was meant to showcase extensions that made use of the new capabilities Mozilla introduced in Firefox 3 and managed to combine this with excellent usability and the use of open standards.

Pencil, one of the three Grand Prize winners, is an easy to use tool for GUI prototyping and diagramming, which makes uses of Firefox's SVG support for rendering and scripting. It's obviously not the most exciting of applications, but it works as advertised and is a great tool for anybody who needs to draw up a GUI prototype quickly.

The second Grand Prize winner, Tagmarks, adds a set of icons to your URL bar that allows you to easily add tags to your bookmarks or to quickly bookmark and tag a page at the same time. Out of all the plugins in the contest, this one is probably the most immediately useful. Adding tags to a bookmark can be useful, but few people make use of this capability. Tagmarks also allows you to safe your links to Delicious in addition to your local bookmarks.

The third Grand Prize winner is also a tagging extension: HandyTag. HandyTag suggests tags for your bookmarks based on the tags you have already used, tags given by Delicious users, and tags HandyTag's keyword extractor suggests.

Fire.fm

Fire.fm, the best new music add-on, gives you easy access to your stations on our favorite streaming music site, Last.fm. Fire.fm works exactly as advertised and provides a nice way to play music through Last.fm without having to keep a browser window open. You can also easily access your favorite stations by just typing in a few letters into the URL bar.