The number of people in the U.S. and Canada who check Facebook every day dropped between the third and fourth quarter of 2017, the first such quarterly drop in company history.
Facebook usage in North America has been largely flat for the last several years, leaving international growth to pick up the slack. But the drop suggests that Facebook usage has reached a saturation point in its first and most lucrative market, and could foretell similar usage drops around the world.
The drop could also be a result of a steady drumbeat of negative press about Facebook, including concern over foreign governments using Facebook posts to divide the U.S. electorate during the 2016 election season, and growing concern over violent and other inappropriate content on the site.
If usage flattens, Facebook will have to pack more ads into the News Feed, charge advertisers more per impression, or figure out new and similarly profitable business areas to maintain long-term growth.