Facebook tweaks prompt fall in user time
Facebook's overhaul of its News Feed has reduced the amount of time people spend on the site and contributed to a quarterly decline in users in the US and Canada, the social network said.
The firm has been making the changes amid increasing scrutiny of its ad business, role in political campaigns and broader social impact.
Boss Mark Zuckerberg said the tweaks would help the firm in the long-term.
He called 2017 "a strong year ... but ... also a hard one".
The comments came as the firm released its latest results.
Facebook's revenue soared 47% last year to more than $40bn (£28.2bn), while profits jumped 56% to nearly $16bn.
The gains came despite an unexpected $2.3bn tax payment due to the new US tax law, which included a one-off tax on overseas profits.
But Mr Zuckerberg said the firm takes "very seriously" ongoing debate about the utility of social media sites and wants to ensure time spent on the network is "more meaningful"