‘Second-screen’ TV viewing: A potential profit center

October 4, 2013, 2:37 PM UTC

FORTUNE — During the extremely tense opening moments of Sunday’s Breaking Bad finale, someone on the East Coast wrote on Facebook (FB), “Breaking Bad … CAN’T BREATHE.”

Which seemed odd. This man was expressing an intense reaction to an intense, riveting scene, even as the scene was unfolding — and yet, for some reason, was motivated to look away from the TV screen to another screen to express those reactions in real time to his friends. To him, the second screen was, for those several seconds, more important to him than the first screen, even though he was clearly experiencing a deep, emotional response to what was happening on the first screen — the very thing he was choosing to ignore.

This is what is baffling about the real-time second-screen phenomenon. It clearly exists, but for many of us (mostly — but not exclusively — people of a certain age) it’s mystifying, sort of like those people next to us at a concert who insist on talking loudly during the entire show — about the show.

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Baffling or not, though, social networks are trying hard to exploit this purposefully attention-deficient demographic. Not to say that all the second-screeners are turning their attention away from heart-stopping scenes where every second counts. Many of them are sharing their thoughts with their friends in between baseball pitches or football plays. Or during commercials. It’s that last one, of course, that has the ad industry worried and looking for ways to take advantage of what is otherwise yet another example of technology making advertising more challenging.

As the New York Times reported, Facebook and Twitter on Monday were quick to brag about how many people were talking about the Breaking Bad finale on their social networks. Both companies “see the social conversation around television as a way to increase use of their sites and win a bigger piece of advertisers’ spending,” the Times said. Nielsen’s SocialGuide (NLSN) says that 600,000 people on Twitter posted more than 1.2 million messages (including retweets) about the finale over a 10-hour period. Facebook says that over 24 hours, 3 million people had something to say about the finale, or at least clicked “like” on a post or comment about the show.

The networks are using such data to try to lure advertisers that might otherwise spend for TV time. And if people are jerking their heads back and forth between two screens, it might make sense for advertisers to try to follow them. People can shut out TV commercials, but ads on social networks — while being easy to scroll past — are hard to ignore completely.

A forthcoming report by eMarketer, cited by the Times, concludes that about half of all Americans look at their social networks while watching TV, and one in six post something about that they’re watching. This happens most often with sports.

And the targets of ads aren’t just the people posting, but the people who are only reading posts about programming — that raises the potential audience by a factor of 50.

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The whole thing makes for a complicated relationship between the social networks and the TV industry. Facebook and Twitter after all, are pretty much trying to leech ad revenues from an industry they are simultaneously trying to court. Facebook, for example, is planning to start running auto-starting video ads sometime in the next few months. If it can do so without alienating Internet users who find such ads incredibly annoying (no easy task), that will put the company in even more direct competition with TV. But Facebook is also making deals with TV networks to give them access to available data on the network — such as comments and “likes” — that’s related to their programming.

Advertisers and network executives told the Times that Twitter for now is way in front of Facebook in terms of TV-related opportunities. One reason is that the faster, more wide-open nature of Twitter makes for a more natural and better-scaled experience of second-screen TV-viewing (Facebook officials “privately” admitted as much). So the race is on.

While it might be disheartening to contemplate a nation of viewers who can’t settle into a single activity at a time, the fact is that we live in such a nation, and the phenomenon will likely only grow more common. So you can’t blame social networks and advertisers for wanting to capitalize on it.