Better Twitter is a user script that runs using the Firefox Extension Greasemonkey. It adds a retweet button to updates, enables auto-load to your Twitter stream, and shows in-line conversations of “in reply to” tweets.
You need to have Greasemonkey installed in order to install Better Twitter, but then you’ll be able to reply to tweets when viewing a single tweet, view “in reply to” conversations in-line, and more.
If you’re into more advanced features, you may want to check out PowerTwitter (previously reviewed here) although I found that it slowed Twitter down so much that I eventually had to uninstall it.
To see Better Twitter in action, watch the screencast below (best viewed in HD in full screen):
[wpvideo xwlBsVKO]
[via Lifehacker]