Data isn’t just valuable for social media giants like Facebook (FB) and Twitter (TWTR) — but also for the stars who attain fame on the platforms. In a newly released interview, top beauty influencer Huda Kattan says she closely studies user engagement metrics to generate viral posts.

Kattan launched a beauty blog in 2010 and has since amassed 39.6 million Instagram followers, giving her a spot along the way on Time Magazine’s list of the most influential people on the internet alongside model and TV host Chrissy Teigen and yes, President Donald Trump.

“We were studying everything,” Kattan says. “We know now data is so powerful, and you can learn so much about yourself and creating product with data.”

By scrutinizing user reactions, Kattan learned exactly how to put together a successful post, she said.

“Studying what people were liking, what they weren't liking, small little things about, you know, would this photo get more likes,” she says. “So we were able literally to create product and packaging based on all those things.”

A makeup video posted by Kattan on Tuesday, for instance, has been viewed 1.6 million times; another, posted a day later, has already been seen more than 1 million times.

Kattan’s millions of Instagram followers go to her for tips on the latest beauty trends and products, helping her build a net worth of $610 million, according to Forbes. Huda Beauty, her company, sells a line of beauty products, and is set to launch Huda Beauty Investments, which will mentor and fund entrepreneurs in the space.

While some top Instagram influencers make hundreds of thousands of dollars for sponsored posts, Kattan said she rarely uses them these days.

"We're not doing promoted posts too much right now,” she says, in response to a question from Yahoo Finance Editor-in-Chief Andy Serwer about how her business operates.

“Our shop Instagram account does, but other than that, we don't really do too many promoted posts anywhere else,” she adds.

Kattan made the comments during a conversation that aired in an episode of Yahoo Finance’s “Influencers with Andy Serwer,” a weekly interview series with leaders in business, politics, and entertainment.

In addition to data, Kattan credited low-dollar Facebook ads as vital to her rise on the internet.

“We didn’t have a lot of money, so we were using $10 ads on Facebook, which was amazing,” Kattan says. “That really helped us cultivate a following on the blog.”

The targeted ad purchases helped build an international following, said Kattan, the American daughter of Iraqi immigrants who now lives in Dubai.