I was discussing this recently with some collegues, debating whether or not Facebook or Twitter can be leveraged to guess who our next president will be. Obviously it's hard to rely solely on metrics provided by the sites. For example, just because you dislike a candidate doesn't mean you won't follow them on Twitter, and many people discuss a candidate (good and bad chatter) without Friending them.
Socialbakers attempted to take on this question, tracking "more than 10 million Facebook Pages and Places, and billions of individual user interactions through December to measure engagement and changes in online candidate popularity."
So, what'd they find? "'Viral Reach,' determined by Socialbaker as Likes and comments multiplied by the average number of friends per Facebook user, suggests that Ron Paul holds the highest overall with 59,554 comments this past week. Rick Perry had the most engaging single-post among candidates, followed by Jon Huntsman and Newt Gingrich.