I combined screenshots of the four major browsers on Twitter. The results are very interesting from a social media perspective:
- IE tweets the most (followed by Firefox, which tweets about 1/3 less than IE)
- Firefox by far follows the most tweeps
- Firefox has the most followers (followed by Chrome and IE, which are comparably close)
(Click on the image for a hi-res version.)

I couldn’t find a twitter account for Safari (that looked legit). If there is one, please let me know and I will include it.
Maybe it’s worth noting Maxthon and RockMelt.
http://twitter.com/rockmelt
http://twitter.com/maxthon/
@cable, thanks for the suggestions. I haven’t used either browser, but might give them a go.