Social network Facebook is making changes to its algorithm that determines what stories show up in its users’ News Feeds. The update will give major news events like the Ferguson riots more priority, so that people can share and discuss these stories as they unfold. Facebook has also been able to convince advertisers to spend on high user engagement. An eMarketer report shows marketers’ digital ad spending share is higher than the share of time people actually spend on Facebook.

According to eMarketer’s new report, 9.7 percent of digital ad spending in the U.S. goes to Facebook ads. Meanwhile, only 6 percent of U.S. adults’ digital media time is spent on Facebook.

For other media, the share of digital ad spending is typically much less than the share of digital time spent. For example, U.S. adults listen to digital radio 11.2 percent of the time that they are on the Internet. However, advertisers only spend 4 percent on digital radio advertisements.

Facebook is able to attract so many advertisers because the social network continues to grow and users increasingly spend more time on it. The Wall Street Journal reports that U.S. adults are now spending an average of 21 minutes per day on Facebook, compared to only six minutes in 2010.

That time will only increase as the network continues to add millions of users. Unlike digital radio that can play in the background, people on Facebook are often actively scrolling through posts and interacting with their friends.

The company is hoping that their changes to the filtering system on News Feeds will help engage users even more. Early testing has shown a 6 percent increase in people commenting, liking, sharing, or clicking on posts, according to The Wall Street Journal.

This change comes in response to the Ferguson riots, which blew up on Twitter immediately. It took days before Ferguson stories started showing up at the top of News Feeds.