The key is going to be finding cost-effective ways to manage their social media presence without taking them away from their “real” job. Being a small business however, I find social media much effective where we can keep up with real-time promotional posts/tweets about buy a home , selling homes, etc.

That said, Google is already using the social graph to deliver results – look at the bottom of the SERPs after running a search, and you'll often see something like “Results from people in your social circle for….” Ranking sites highly based on the gross # of “likes” (or the equivalent) is problematic b/c there's a high potential for abuse (which is why Google puts little to no weight behind user input when people bump sites up or down the SERPs in personalized search.) However, if Drew's in my social circle, and Drew likes a specific website about cupcakes, there's a % likelihood that I will also like that site. So, graphing and ranking sites based on what your social circle also likes is relevant.

Anyways…just my .02! Speculation, but I like to think it's informed.

I disagree with Sam that links are more valuable because they are more deliberate than simply clicking a like button. The reality is that the majority of people consuming material are not bloggers or website owners, and have no way to create a true backlink. By factoring in actions on social media sites, the search engines would be able to see what the bigger audience gives authority too rather than focusing on just what other website owners prefer.

A consumer clicking “Like” takes two seconds. A web site developer/owner linking to another site is a deliberate, information-directed action. Real links will still have much more weight, I'd imagine.