Facebook announced a new audio recognition feature today, billing it as shortcut to help its users more easily share what they are doing. But another likely motive for Facebook is to gather more data about users’ entertainment viewing habits to be used as ammunition in the battle with Twitter for second-screen territory.

The new feature, which will be rolled out on Facebook’s iOS and Android apps in the coming weeks, tunes into background noise using the mics on users’ phones. If the app finds a match for a song or a television show, it will suggest a relevant tag.

For songs that it recognizes, it will pull a 30-second preview into the post; for TV shows it will indicate the specific season and episode being watched, “so you can avoid any spoilers and join in conversations with your friends after you’ve caught up.”

Facebook emphasized that the feature is opt-in and that the app is only listening for recognition purposes and not recording audio.

However, Facebook will obviously be recording and storing data about user behavior, which at some point will certainly be used for advertising targeting purposes. Facebook far trails Twitter in the public-conversation-about-news-and-entertainment sphere so it has huge incentive to emphasize that people use its platform to talk about the same.

By specifically associating these often private Facebook updates with entertainment franchises will no doubt help make the point to advertisers that its audience dovetails nicely with the people glued to their TVs.

And as usual Facebook’s response to questions about ad targeting was somewhat coy. Here’s what Facebook product manager Aryeh Selekman told TechCrunch’s Josh Constine:

“On the ads front, no one is able to target these posts directly today,” Selekman says. However, he admits “it’s definitely something we’ve thought about and will potentially do in the future.” For example, if you posted that you were listening to the new Beyoncé album, you could one day be targeted with ads for the singer’s new concert tour.