Firefox has long been the darling of geeks everywhere, but its popularity has waned lately, mostly due to competition from Google’s Chrome browser. Firefox, while stable and practical, simply wasn’t as quick as Chrome. Some, such as myself, switched.

Now Firefox 4 is out, and the browser has been substantially redesigned to improve performance and offer a better interface. The add-on ecosystem always changes when a new browser version is released, and Firefox 4 is no different. Many older add-ons are broken – at least for now. Fortunately, there are a few new or revised add-ons already available.

Movable Firefox Button 1.3

This add-on makes the Firefox button in Firefox 4 movable. By default, the button hangs out in the upper left hand corner, on the same part of the interface used by tabs. This add-on lets you move it to someplace else, such as alongside the search bar, which frees up more room for tabs to appear.

FabTabs 1.4

The concept behind FabTabs is simple – make tabs visually distinct. That way, you’ll be able to tell the sites you have open in your tabs at a glance, without reading any text. This is great for users who like to open lots of tabs, as having large numbers of tabs open forces each tab to become smaller, which soon makes the text useless.

Fab Tab accomplishes this by taking a screenshot of the website you’re viewing and working some math wizardry to find the most prominent color, which it then applies to the corresponding tab. Although this sounds easy to fool, it worked perfectly in my usage. It even picked red for CNN, despite the fact that most of the website is white.

Easy App Tabs 3

One of the new features in Firefox is the “app tab.” This is a small tab that is used to mark websites, like Facebook, that you want to use but don’t need to devote an entire tab to. By default, app tabs are placed by right clicking and then selecting Pin as App Tab from the menu, but Easy App Tabs lets you do the same by simply double-clicking a tab. It’s quicker and easier.

Vertical Toolbar 0.2

Opera users might like this one, has the purpose of Vertical Toolbar is to add, well, a vertical toolbar – which looks quite a lot like the one Opera has when you open the “panels” toolbar. Firefox isn’t Opera, though, so there isn’t quite as much stuff to put on the toolbar by default. You gain access to your bookmarks, browsing history and download manager at the top, while at the bottom you’ll find buttons for full screen view, printing and refreshing the page.

Things get more interesting if you open up the Firefox button, go to Options, and then go to Toolbar Layout. There are a number of toolbar functions listed here that aren’t included by default but can be added easily. If you have installed the Movable Firefox Button 1.3 add-on you can place your Firefox button on the vertical toolbar as well.

Tab Badge 1.2

As websites command more of our attention and become more like apps, notifications become more important. A program has no problem telling a user when something has happened, but that sort of behavior isn’t common from a web browser.

Tab Badge seeks to resolve this issue by adding a small, bright-red visual notification on open tabs of social networking and email sites. This add-on works with Twitter, Facebook, Gmail and more.

Instant Preview 3

This add-on is straight from Mozilla Labs, which means its a feature that didn’t quite make it into the full web browser, but is being worked on and considered for future use. Once installed, pages that show up in the search bar when you are typing will begin to load automatically. Once you click on them, they’re already partially or completely loaded, creating a web experience that feels smoother. However, this behavior will only work with websites you have visited before, which is the add-on’s one downside.

Custom Tab Width 1.0.1

Another simple but useful interface tweak, Custom Tab Width lets you determine how wide or small a tab can be. By default, Firefox limits tabs to a maximum width of 250 and a minimum width of 100. If you’re a tab heavy user, though, you can use this add-on to reduce that minimum width to whatever you’re comfortable with. This is a great add-on to use with FabTabs.

Conclusion

Usually, this is the part where I point out that there are lots of add-ons available, I can’t possibly cover them all, and I’ve selected those I’ve found most useful. To some extent, that applies. But the list of add-ons for Firefox 4 is small at the moment, so the 7 listed here represents about 25% of all Firefox 4 add-ons currently available!

Of course, folks will be quick to jump on the bandwagon, so the list should expand rapidly. Mozilla has a special “Only for Firefox 4” section set up on their add-on page, so you might want to bookmark it and check back in a few weeks to see the new add-ons that have been released.