Move over Internet Explorer, Firefox, Safari and Chrome. If a new browser startup backed by Netscape co-founder Mark Andreessen’s VC firm, Andreessen Horowitz, has its way, consumers will soon be surfing the internet in a far more social way.

RockMelt, which is launching in beta, is “challenging the conventional assumption that a browser is all about navigating pages.”

The company’s first blog post explains:

With RockMelt we’ve re-thought the user experience because a browser can and should be about more than simply navigating Web pages. Today, the browser connects you to your world. Why not build your world right into your browser?

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. Your favorite sites are important to you, so we built them in too. Now you can access them from anywhere, without leaving the page you’re on. And RockMelt will tell you when something new happens.

On paper, RockMelt, which is built on Google’s Chromium open source browser project,  looks intriguing. Consumption habits on the web have changed, and as we’ve seen in the mobile space, there are plenty of opportunities to create user experiences that allow consumers to interact with existing content and applications in new ways that are consistent with those changing consumption habits. From the looks of it, RockMelt is making a decent attempt to make using the internet and popular social networking services like Facebook a more seamless exercise.

Despite all this, it’s hard to see RockMelt gaining much mainstream traction any time soon. The browser market is highly-competitive and will be a very tough nut to crack. As a Facebook account is required to use RockMelt, the company has inherently limited its market to Facebook’s 500m registered users, and will have to convince them that there are no privacy issues with logging in to browse. Perhaps most importantly, history is not on RockMelt’s side. As others have noted, the makers of the Flock browser have done a good job making the browser more social but they haven’t been rewarded by the market for it.

At the end of the day, there is no doubt that, for many consumers, using the internet has become a ‘social‘ experience. But it’s quite unclear whether or not there’s a need for an additional layer of ‘social‘ at the browser level. Even for a billion-dollar behemoth like Google, browser market share is hard won. Reinventing the browsing experience, marketing that new experience and educating consumers will not be easy, nor will it be cheap. RockMelt had better hope Andreesen Horowitz, which just raised a new $650m fund, is willing to write a blank check.