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Scroll through your Facebook feed, and you'll get pelted by advertisements begging for a click. Like any other type of post, these ads allow you to react. Often, you'll notice that one or more of your friends has already "liked" them.

Advertisers hope that a high number of such endorsements, especially from familiar faces, might make users more likely to click. But new research from Texas McCombs finds it depends on the type of ad—and the type of friend.

The wrong ads and friends could have the opposite effect, making a viewer less likely to click. So say Ashish Agarwal, associate professor of information, risk, and operations management (IROM), and Andrew Whinston, professor of IROM. Whinston is also the Hugh Roy Cullen Centennial Chair in Business Administration and director of the Center for Research in Electronic Commerce at The University of Texas at Austin.

Agarwal, Whinston, and Shun-Yang Lee of Northeastern University focused on call-to-action (CTA) ads. Such ads use assertive wording to urge users to do something specific, such as purchase a product or download a mobile app. They're different from the passive wording of informational ads, which politely invite users to click to "learn more."

Advertisers tend to prefer CTA ads, Agarwal says, because they put social media users "directly into purchase mode." But past research had shown a downside to CTA ads: They often rubbed users the wrong way, especially when people felt manipulated.

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