Social TV ads are coming to Facebook in an effort to compete with Twitter’s television advertising model. Now, advertisers will be able to reach Facebook users online at the same time an ad is running on TV. For example, an advertiser that airs a commercial on a local station in Los Angeles will be able to simultaneously target users in Los Angeles who are logged in to Facebook at the same time. And that’s some prime real estate.

For some time, Twitter has had the advantage over Facebook in this realm. (The site offers ad targeting that exposes users to a brand on TV and in their timelines.) Facebook finally caught on to the money-making potential of this format. So from now on, within seconds of an ad airing on TV, that same advertiser will appear on targeted Facebook news feeds.

“An advertiser just decides which TV ads they want to use as triggers,” said Rob Leathern, founder and chief executive of Optimal, a San Francisco social advertising company.

According to The New York Times, Optimal is working with the Dutch company, Civolution, “whose computers watch TV channels worldwide in real-time and catalog everything running on them, including the ads.”

“We’re basically betting, and our advertisers are betting, that some portion of the audience is on Facebook,” Leathern told NYT.

And it’s a good bet, considering this year, for the first time ever, adult Americans are spending more time on digital devices than they are watching TV, according to eMarketer (reported by ETCentric in August).

Optimal announced the new targeting program on Wednesday. Though it’s an operation by Optimal and not Facebook, positive results could make for a permanent change in the way Facebook offers up advertising.

“If social TV advertising turns out to have staying power, there is another tantalizing possibility: another company could aspire to be the online water cooler for Internet users and advertisers interested in television,” notes NYT. “Civolution said its global TV scanning data can be connected to any real-time ad bidding service for any digital platform. So if, say, Google or Yahoo or a foreign site wanted to build its own hub for conversation about TV, Civolution could easily provide the data to help time the ads.”