Firefox users have long been able to select from a vast assortment of free extensions that add functionality--ranging from improved RSS reading to security enhancements to ad blocking--which increases that browser's appeal to many users. IE 7 is taking aim at that advantage with a new add-on manager, as well as an accompanying Web site to promote and distribute the extras.
Microsoft doesn't quite hit the target, however. You can enable, disable, and delete add-ons in IE's manager, but it's not very user-friendly; for example, the manager offers no descriptions of the add-ons. Also, to see all possible extensions, you must go through four categories that themselves are far from intuitive: add-ons currently loaded in Internet Explorer, add-ons that have been used by IE, add-ons that run without requiring permission, and downloaded ActiveX controls (32-bit). Moreover, to update your plug-ins, you must manually check for new versions and download each one.
By contrast, Firefox 2 builds on a good thing with a revamped manager that controls themes and extensions in one window. As before, each one has a description, and a Find Updates button quickly checks for updates for every add-on.
It can be great fun to tinker your way to a fully customized browser with extensions, but you can risk slowing things down by using more system resources. Firefox users have griped about its memory usage in the past, and while Mozilla often blames add-ons, the company says version 2 uses significantly less memory than version 1.5 does.