Extensions and Add-Ons
Some of the best browser features aren't even the work of the major browser developers. Instead, independent programmers have taken to the Web in droves, creating amazingly useful add-ons that you can download and install for free. But not all browsers support all the same extensions, and some barely support them in general. As a result, add-on support has become a major differentiator between browsers. When judging the five top browsers, we looked at the types of add-ons each one allows, the selection of available add-ons, and how easy it is to find, install, and remove add-ons.
Internet Explorer 8
IE 8 permits you to install assorted browser toolbars--including those search toolbars that you either love or loathe. IE 8 also includes Web Slices and Accelerators. Web Slices are add-ons that allow you to keep tabs on tidbits of information from around the Web without your having to visit the sites. For example, the eBay Web Slice allows you to track the status of auctions, while the USA Today Entertainment Web Slice lets you quickly view the top showbiz stories. These usually live in your IE favorites bar, and open with a click.
Accelerators, on the other hand, are shortcuts for tasks that you perform in your browser. For instance, if you highlight a block of text, a blue icon appears next to it. If you click on that, you get a menu that lets you translate the selected text, search for the selected text, look it up on a map (if it's an address), and so forth. You can see the entire library of IE 8 add-ons at Microsoft's aptly named Add-ons Gallery.
Firefox 3.6
Firefox first championed browser extensions several years ago, and though other browsers have played catch-up since then, Firefox retains the add-on crown. Mozilla has a library of thousands upon thousands of add-ons and extensions for your perusal, ranging from security add-ons to social networking tools to stuff for Web nerds, and just about everything in between. By going to Tools, Add-ons in Firefox, you can view and enable or disable installed extensions, themes, and plug-ins, and browse through recommended add-ons.
The one shortcoming of Firefox is that updating extensions can be more obtrusive than I'd prefer. I'd like to see Mozilla make updating extensions something that happens in the background.
Chrome 5
Chrome rolled out extension support late last year, and Google's extension library already has a healthy selection of add-on goodies that can take the form of toolbar icons, notifiers, weather updates, and more. Extension updates happen more seamlessly in Chrome than in Firefox, and the extensions are better integrated into the browser. That said, Chrome can't quite match the breadth and selection of add-ons that are available for Firefox.
Safari 5
Safari is a little late to the extension party; extension support is new to version 5, and as of this writing extensions are few and far between. At least one blog out there posts about Safari extensions, though, and Apple is planning to launch an extensions gallery in the near future--it may be up and running by the time you read this.
Opera 10.6
Opera takes a completely different approach with its widgets. Much like the desktop widgets in Windows 7 or on Mac OS X's Dashboard, these are mini-applications that can provide quick updates on news, weather, sports scores, or what have you. One thing to note is that Opera Widgets aren't add-ons in the classic sense--they don't run within the browser itself. Instead, they're separate, stand-alone applications that run alongside your other software. This means that they stay open even when you close Opera, which can be useful, but they do little to extend the functionality of the browser.
BEST EXTENSIONS: Firefox
Though there's a lot to like about the add-on support in other browsers, Firefox still takes the prize in this comparison, mainly because its extension support and extension library are already mature and well established.