The Mozilla Uninstall Survey website has been retired as of December 2010.
Before setting up programs like Test Pilot, we used to collect data to learn about why people uninstalled Firefox. The survey.mozilla.com website is no longer in used but the data is available here and there might be some interesting things to still to learn.

use it all the time. It’s crashing for some reason so I uninstalled and now wil reinstall.
I found it difficult to use at first. It was also slow. I have an older computer, so that might be the reason. Otherwise, I think it is a good browser and it came highly recommeded from a friend who builds computers.
quite possibly the worst thing I have ever put on my computer, extremely slow loading, where as IE9, Chrome load instantly, firefox takes over 2 minutes to load (on a brand new machine too)
Firefox makes the computer extremely slow while uploading the browser …
I can understand why mozilla is retiring this comment thread. although I love foxfire, it is geting worse and worse all the time.