San Francisco — Facebook's efforts to crack down on misinformation and sensational content have reduced the time spent at the leading social network eroding, researchers said Tuesday.

The average amount of time US adults spent at Facebook dropped by three minutes per day last year and will likely decrease by another minute next year, to a total of 37 minutes daily, according to the research firm eMarketer.

The report suggests that Facebook chief Mark Zuckerberg's efforts to focus on safety and remove divisive and hateful content could be having an economic impact.

"Facebook's continued loss of younger adult users, along with its focus on down-ranking clickbait posts and videos in favor of those that create 'time well spent,' resulted in less daily time spent on the platform in 2018 than we had previously expected," said eMarketer principal analyst Debra Aho Williamson.

"Less time spent on Facebook translates into fewer chances for marketers to reach the network's users."

Money taken in from digital ads are the leading source of revenue at Facebook, which has 2.4 billion monthly active users around the world.

A bright spot for Facebook is that daily US engagement is creeping up at its image and video focused social network Instagram, where eMarketer expected it to rise a minute this year to 27 minutes and then another minute per year through 2021.

"Features like Stories, influencer content and video are all contributing to more engagement and a slow but steady uptick in time spent on Instagram," Williamson said.

Meanwhile, time people in the US spend at Instagram rival Snapchat has seemingly plateaued at 26 minutes daily, with an application redesign failing to boost engagement, according to eMarketer.

A broader trend seen last year was for Americans to spend less time at online social networks, and the overall engagement was expected by eMarketer to remain unchanged this year at almost one hour, 14 minutes per day.

"Gains in digital video viewing are putting pressure on social time, and gaming is also creating new competition for user attention," Williamson said.

"Though we can't say there is a direct cause-effect relationship, these activities do at least threaten users' engagement with social media." — AFP