While marketers have long targeted online radio listeners baed on their zip code or gender, this type of interest-based targeting is new. The ad options, which are the result of a deal between radio service Triton Digital and data provider eXelate, mean radio ads are about to get a lot more specific.

According to Triton Digital COO, Mike Agovino, radio ads represent a $17 billion industry but one that relies on out-dated metrics and that offers little accountability to ad buyers. He thinks that letting brands sell to listeners based on their web surfing habits will drive a new wave of automated ad buying and increase the value of the radio ad market.

The possibilities for radio are intriguing. Recall that, in the recent Presidential election, the parties launched a barrage of political ads in swing districts by using Pandora’s ability to play ads based on a person’s zip code. Meanwhile, their neighbors across the street who lived in a different district might have heard ads for trucks or lollipops based depending on their age and gender (Pandora garners this information when you sign up for the service).

Now, radio ad targeting is going to get even more focused. For instance, the new data tools mean Ford might sell pick-ups after a teenybopper song because the company knows a listener was just looking at truck sites. Or Tampex may find occasions to pitch its products in the midst of a heavy-metal marathon.

According to eXelate CEO, Mark Zagorski, radio is the “last bastion of context based advertising” but that this will change quickly due to online radio’s growing popularity and the capacity of behavioral-based advertising to scale quickly.

As with other situations in which marketers use big data techniques to pitch products, there is a creepiness factor here. For instance, do you want marketers to know you’ve spent the last two hours researching gonorrhea and play you radio ads accordingly? Zagorski addressed the privacy concerns by saying that eXelate doesn’t touch so-called PPI (private personal information) but simply overlays online activity onto a streaming service.

The new interest-based ads will help brands reach users of Pandora, which makes up about 74% of the online radio market, but also the web streams of more traditional radio stations as well.

Spotify told Bloomberg it has “no announcements to share at this time,” but:

The new format would be similar to Pandora’s, which operates like radio and is cheaper to operate because royalty rates are lower and set by Congress.

The new service would start by year-end and be supported by advertising, said the people, who weren’t authorized to talk publicly. The company has begun notifying some content partners of its plans, they said.

In the most recent figures released, Spotify said it has 10 million registered users worldwide and three million paying subscribers. Pandora has 150 million registered users.

Spotify already offers a radio feature on its desktop app, but it is not mobile yet.

Bloomberg explains Pandora users “have access to any artist whose music has been published, because the service operates under federal rules. Royalties paid by Pandora and other online radio companies are set by the Copyright Royalty Board, a division of the Library of Congress.” So a radio service would allow Spotify to offer some music it doesn’t have the rights to already, and could also pull needed advertisers to the platform.