Installing these Firefox extensions, like installing any other Firefox extension, is just a matter of clicking the shiny green Install Now button from the extensions' homepages. You'll find both the extensions enabled after a browser restart to complete the installation.

One of the major reasons Firefox is approaching 400 million downloads is because of how customizable the browser is thanks to extensions. In a way Firefox extensions are bittersweet, because they can provide some unique and useful features, but at the same time they can cause some unwanted problems.

I recently searched through the mozilla thunderbird extensions website and found 4 extensions that I didn't know about that actually prove to be quite useful. I use Thunderbird 2.0.0.12 on Foresight Linux and have tested all of these extensions and verified that they work on that environment. Hopefully, they'll help someone craft a more enjoyable email experience

As with Firefox, you can extend Thunderbird's functionality by installing extensions. Mozilla's official extension repository has quite a few nifty tools on offer, and which ones you choose to install depends entirely on your needs. There are, however, a few extensions that you might find indispensable no matter how you use Thunderbird.

"XUL is a surprisingly easy way to build cross-platform browser extensions or even stand-alone applications. Discover how to build powerful, flexible Mozilla browser extensions that go beyond the capabilities of other tools..."

"Create extensions that go beyond the built-in capabilities of Web browsers. The Mozilla project's XUL engine is a user-interface language that you can use to extend Mozilla browsers, or to build stand-alone applications. XUL is a surprisingly easy way to build cross-platform browser extensions, and this pair of articles demonstrates how."

One of the pains of installing so many distros is configuring Firefox exactly as I would want it; especially this means loading the right extensions (add-ons). Seriously, there are some firefox extensions (add-ons) that I can’t live without and the following is the list that I need. It’s personal (of course), suited only to my need, so this list is not normative for anyone.

We’ve put together a list of 30+ must-have Firefox 3 extensions that we know you’ll enjoy, whether you’ve upgraded to Firefox 3 and are looking for something new to add to your browser, or have yet to make the upgrade and are looking for a reason.

Sunbird, Mozilla's calendar application, supports extensions just as Firefox and Thunderbird do. What kind of extensions work with a calendar? How about being able to get a weather forecast when you're setting up a golf date, or exporting your desktop calendar to a Web service?