Facebook is cutting down on viral videos as it looks to improve the quality of the time spent on the service.
CEO Mark Zuckerberg announced the move as part of the company's Q4 2017 earnings release.
"Last quarter, we made changes to show fewer viral videos to make sure people's time is well spent," he said. "In total, we made changes that reduced time spent on Facebook by roughly 50 million hours every day."
That announcement, as well as slowing user growth, seemed to shake investors, who sent Facebook's stock down 5 per cent in after-hours trading.
That's despite the fact that Facebook once again had a blockbuster year in 2017: The company revealed on Wednesday that it generated $US40.65 billion ($A56.91 billion) in revenue in 2017, compared to $US26.89 billion ($A37.65 billion) in 2016.
Facebook's daily active users reached 1.4 billion in December of 2017, compared to 1.23 billion in December of 2016. Monthly active users were 2.13 billion, compared to 1.86 billion 12 months earlier.
