Twitter Address Bar Search is an official Twitter add-on for Firefox that lets you search twitter using #hashtag and @username from the address bar in Firefox on the desktop and on Android. The pinned Twitter App tab lights up when new Tweets arrive.
“With the Twitter Address Bar Search add-on, Twitter leverages the extensible Mozilla Firefox platform to deliver an integrated social experience to hundreds of millions of Firefox users worldwide.” – blog.mozilla.com.
We have earlier introduced a similar add-on from Echofon. Check it also.