Rockmelt is a browser that is focused on your social life. If you have used Google Chrome or you are using it, you will be very familiar with Rockmelt's interface cause it is based on Chromium, the same engine that powers the Chrome browser.
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It has integration with GMail, Facebook, Twitter and a whole lot other features that you'll discover on your own. It also has a feature whereby your Facebook chat is online even if you are not on Facebook's website at the moment.