Mozilla releasing Firefox versions frequently like Chrome. This time Firefox 7 released in 40 days with in the release of final version of Firefox 6. If you already using Firefox then update Firefox 7.0 easily.
Firefox 7 features
Memory usage has been improved, you can observe upto 50% improvement in Memory usage, and so speed also increased.
Improved Rendering backend to speed up canvas operations on windows
Firefox sync has been improved, so that bookmarks and password changes effect almost instantly.
Several bugs of Firefox 6 has been fixed.