Most of the mobile display ads that pop-up on our phones don’t mean a thing — We ignore them and keep on tapping and swiping. But a study out of Columbia Business School sheds light on what consumers pay attention to in this booming mobile advertising industry.

Miklos Sarvary, the report’s co-author, directs the Media Program at Columbia Business School. He says if advertisers want mobile users to think twice about their ads, they should offer up useful items.

“These would be products like cars, or refrigerators, or lawn mowers, so pretty high ticket items, generally,” says Sarvary.   

He says important purchases get more attention than pop ups for pleasure items like movie tickets and jewelry.  

“What happens is that when a little ad like that pops up, it kind of makes you think about the decision again,” he says. “So, it reminds you of the information you already store in your mind.”

Jim Davidson is Director of Research at Bronto Software, which connects retailers with customers on mobile devices.

“Mobile really encompasses a lot of different technologies in a lot of ways that folks shop, and it’s really up to marketers to find the best way to have that conversation,” Davidson says.

Sarvary’s report shows nearly $17 billion was spent on mobile advertising last year, a figure that is expected to quadruple by 2017.