RockMelt is an application designed for Facebook users. You will be able to see your friends posts, update your status, etc. from this browser, you can share pictures, videos and music without opening Facebook site at all. It can be as fast as Google chrome because is based in the same open-source code.
When you open RockMelt for the very first time, it will ask you to sign in on Facebook that way you can start using it right from the begining; however you can log out any time you want or log in with a different account. It also has many plug-inns and extensions available in its library.