Everyone who uses Mozilla's Firefox browser knows that it gets much of its power from the thousands of useful extensions available for it. Some Firefox extensions are so powerful that they almost qualify as applications unto themselves, as I find to be true with the awesome iMacros extension. As announced on the Mozilla Add-Ons blog today, Mozilla has introduced Collections, which, among other things, will let you click one link to put a whole set of your favorite Firefox extensions on a new installation of the browser. You can find a video showing how Collections works here, and there are already several useful looking Collections available at the Add-ons for Firefox site (see the right side of the page).
Collections can include Firefox themes and language packs in addition to sets of extensions. You can also create your own Collections, name them, get a unique URL for them, and share them. In looking through some of the first Collections posted, I'm struck by the fact that many people who currently love a particular type of extension may find Collections to be good discovery tools for similar extensions.
For example, we've written a number of times about how beloved the Firebug extension is among web developers. It's an outstanding open source debugger for HTML, CSS, JavaScript, and Ajax that works directly within Firefox. One of the first Collections to be posted at the Add-Ons for Firefox site is a set of 8 add-ons designed to complement Firebug. The Collection is found here.
If you love Firebug, do you know about YSlow, which analyzes web pages and why they're slow based on Yahoo!'s rules for high performance web sites? How about Jiffy, which adds a new panel to Firebug for displaying timing measurements for JavaScript applications? Do you use FirePHP, which enables you to log into your Firebug Console using a simple PHP method call? You can get all these and more in one Collection, with one click to install them, or pick and choose.
There are other interesting Collections already posted. Here's another one for web developers, with 12 extensions. Here's a Reference Desk collection with 13 add-ons for researchers, students, or anyone seeking answers to questions.
While I'm not sure that every user of Firefox will want to install entire Collections of extensions instead of picking and choosing individual ones, Collections look like a very good way to discover extensions that could be useful, especially ones that complement extensions you already like.Â
In other Mozilla news, the company has rolled out a "Build Your Own Browser" program. It's aimed  at enterprises that want to create a customized browser that can be deployed to multiple desktops.Â