IMHO rockmelt (like flock before it) is an elaborately engineered answer to the wrong question - how do we deeply integrate social with browsing? It does indeed so integrate social media aggregation with browsing but the problem is that the implementation is so heavy on the social media that it constitutes noise whilst browsing and is therefore detrimental to the user experience.
Why do you believe that this is the wrong question? Are you pointing to the fact that RockMelt, Flock, etc. are products for which there is no real market? If so, then I agree with you.
That is what I mean. All products answer a question. Unsuccessful ones answer the wrong question. The question may make intellectual sense, it may be tempting - it's just wrong. So you end up with a product without a market. :)
