Microsoft is aware of the problem, and says that it hopes ultimately to make it possible to author add-ons via scripting. But there's no timetable for this.

Beyond that is a cultural issue. There is a sizable community of people who believe in open source as a movement and philosophy, but outside the confines of Microsoft, you won't find a similar community devoted to Microsoft as a movement and philosophy. So you don't have people with the same fervor devoted to writing IE add-ons as you have writing Firefox extensions.

Microsoft doesn't seem to be doing anything to foster an add-on movement, either. The Firefox extension site, for example, is run by the Mozilla Foundation, which plays an integral role in the open-source movement. Microsoft's add-on site, meanwhile, isn't even completely run by Microsoft itself; it's a co-branded download library powered by CNET's Download.com.

The bottom line

IE7 is a clear and dramatic improvement over IE6; with tabbed browsing, increased security, excellent RSS support, better printing, and a cleaner interface, it's a no-brainer to upgrade from IE6.