Extensions are small add-ons that add new functionality to Firefox. They can add anything from a toolbar button to a completely new feature. They allow the application to be customized to fit the personal needs of each user if they need additional features, while keeping Firefox small to download.
If any of the extension links below do not work, go to Extension Central, and search on the name of the extension.
I cannot say enough about how cool this extension is. Especially if you design, edit, or troubleshoot websites. It displays the paths of all images on the page, as well as the file sizes. You can view source by clicking the link in the toolbar, you can check for broken links, and make sure the page is 508 complient. There's TONS more, but I'm just so enthralled with this extension.
This tool inserts an option in the Internet Explorer right click menu that allows you to open new links in Firefox. This is useful if you want to use tools such as the Web Developer toolbar on a link on a page that you've opened in Internet Explorer, or if you've started your browsing session in Internet Explorer
Get international weather forecasts from AccuWeather.com, and display it in any toolbar or statusbar with this highly customizable and unobtrusive extension.
Allows you to launch embed video of website in an external application with a simple click. It allows you to launch embedded video and audio using an external player, such as Windows Media Player. The best application of it's use is to launch internet streaming radio into Windows Media Player, and save it as a playlist. Instead of having to navigate to the radio's website every time you want to listen to the station, simply open the playlist to connect.
This is a pretty cool toolbar that lets you log right into your MySpace account. There are links for the Home Page, Friends, Mail, Blog, Forum, Games etc...
Embedding Internet Explorer in tabs of Mozilla/Firefox. There's an icon in the status bar that allows you to reload the page in Internet Explorer (same tab) or back to Firefox. Also, an option is added to your rightclick menu to View page in IE Tab. Great for using tabbed browsing and one application if you have sites that cannot be viewed in Firefox.