Good to see that Mozilla is "putting the squeeze on slow Firefox add-ons":
http://www.theregister.co.uk/2011/04/03/mozilla_cracks_down_on_add_ons_that_slow_firefox/
With a blog post on Friday, Mozilla said that within the next two weeks, it will add a warning to any add-on that slows Firefox's startup time by more than 25 per cent, and in an upcoming version of the browser, third-party add-ons will not be installed unless the user specifically approves the installation.
"It’s an all-too-common practice of third-party software to install toolbars and other bundled add-ons in your browser without permission," Mozilla says. "We know that these add-ons account for many of the performance problems reported to us, and users often don’t know how the add-on got there or how to remove it." Requiring approval for the installation of all add-ons, Mozilla believes, will have a "huge impact" on performance.