After a few months of tweaking the News Feed in order to make it more personal and harder for fake stories to spread, Facebook says that overall usage has dropped by “roughly 50 million hours every day.”

That’s a huge and potentially scary number for Facebook — its goal, after all, is to get people to use more Facebook and see more Facebook ads — but company CEO Mark Zuckerberg has been warning this moment would come, and he’s argued that in the long run, it’ll be beneficial. The company released the stat today while reporting earnings for its fourth quarter of 2017.

Declined usage is showing elsewhere, too. Though Facebook saw a 14 percent quarter-over-quarter increase in daily and monthly active users, it actually dropped from 185 million to 184 million daily users in the US and Canada and stayed at a flat 239 million for monthly users. And while usage grew in all other measured regions, growth was slower than it’s been since 2015, as Recode points out:

Facebook's daily active users grew to 1.4 billion. While that's up 32 million from last quarter, it's the slowest quarter over quarter growth since 2015. $FB pic.twitter.com/QSNU1eUrmO — Recode (@Recode) January 31, 2018

Zuckerberg warned about the decreased usage earlier this month, saying it was an expected effect of the changes being made. “But I also expect the time you do spend on Facebook will be more valuable,” he wrote. “And if we do the right thing, I believe that will be good for our community and our business over the long term too.” Zuckerberg said changes started to be made in 2017, but that it will “take months” for it to be seen across all of the company’s products.

“In 2018, we’re focused on making sure Facebook isn’t just fun to use, but also good for people’s well-being and for society,” he said in a statement this afternoon. “We’re doing this by encouraging meaningful connections between people rather than passive consumption of content ... By focusing on meaningful connections, our community and business will be stronger over the long term.”

In November, Facebook said its commitment to “preventing abuse on our platforms” would “impact our profitability,” and it may already be feeling that to an extent. For its final quarter of 2017, Facebook brought in $13 billion in revenue and $4.3 billion in profit, up from $8.8 billion and $3.6 billion this time last year. But even though it grew, profits still missed investors’ expectation, rising only 19 percent on a per share basis instead of closer to the 60 percent that investors were looking for, according forecasts reported by The Wall Street Journal. Facebook’s full-year numbers for 2017 saw substantial increases, jumping up to $40.6 billion and $15.9 billion, from $27.6 billion and $10.2 billion in 2016.

Correction January 31st, 5:43PM ET: This article initially referred to user growth statistics as year-over-year, instead of quarter-over-quarter.