How social is your favorite TV show? Bluefin Labs knows.

TV viewers are increasingly engaging in social media while watching their favorite shows. But which shows are drawing the most commenters and the largest share of the conversation? Cambridge, Mass.-based startup Bluefin Labs is using social media to not only measure engagement during TV shows, but also to find connections between shows that those viewers enjoy watching.

The company’s Response Level and Response Share metrics are essentially new ways to think about how a TV show stacks up against the competition. The new metrics are designed to measure how audiences talk about shows, both in terms of total number of commenters on a show, and the percentage of that show’s share of the conversation during the time in which it aired. And it’s rolling out its Bluefin Signals dashboard as a way for broadcasters and advertisers to see the connections between these shows and conversations.

The platform determines what people are commenting on without the more traditional use of scanning for hashtags or keywords during a certain show, using video fingerprinting technology to determine what’s happening onscreen instead. It then matches TV action with social media response. Deb Roy, co-founder and CEO of Bluefin, Labs refers to this matching up as “mapping the TV Genome.”

The platform measures social media responses to more than 3,000 TV shows and more than 100,000 individual airings of those shows. Each month, it processes about 3 billion social media comments, matching them up against 2 million minutes of live TV during that time. The company hopes to have full coverage of all live TV shows next year.

While knowing how many viewers are commenting about a particular show might be of some value to broadcasters and advertisers who use social media sentiment during a show as a proxy for engagement, the more valuable tool might be in Bluefin Labs’ ability to draw connections between shows. This data on “cross-show engagement” is useful in determining affinity between shows — for example, recognizing that fans of One Tree Hill are also likely to watch Hellcats and 90210.

That data can be used by broadcasters to help increase viewership — for example, running small ads on one show to promote another that fans might also like. Or it can be used by advertisers: If ad inventory on one show is in high demand, but its viewers have an affinity toward a show with a lower profile, agencies and brands can reach the same group of people with a less costly ad buy by betting on the second show.

Bluefin Labs isn’t the only company striving to measure social engagement with TV: Wiredset’s Trendrr recently introduced a social media TV chart, and SocialGuide aims to track social media mentions of shows in real-time.