This blog post is the source of the story. Some quotes:
"Share or tweet links often? Yeah, us too. No more wading through each site’s goofy share widget or copy-pasting URLs. We built sharing directly into the browser, right next to the URL bar. Like a site or story? Click “Share” and BAM – link shared."
"Behind the scenes, RockMelt is always working on your behalf. Do you visit the same site 10 times a day, checking for new posts or updates? Well, RockMelt keeps track of all your favorite sites for you, alerting you when a new story comes out, a friend posts new pictures, or a new video is available. And when you open a RockMelt feed, the content is already waiting for you."
None of this sounds world shattering.
"Your friends are important to you, so we built them in. Now you’re able to chat, share that piano-playing-cat video everyone’s going to love, or just see what your friends are up to, regardless of what site you’re on."
Browsing together with friends and commenting is promising. Others have tried and failed, but maybe they can get it right. Some more analysis at the reg.