Facebook went down this afternoon, apparently for about an hour, the social network confirmed.

"A Facebook-wide issue is causing the Facebook Graph API to be temporarily unavailable," the company said. It was "working with our core infrastructure teams to identify the issue." A fix had been finished by about 4:10 p.m. ET, though it had not yet been deployed.

The site first went down at about 3 p.m. ET and was functional again for some users by about 4 p.m. ET, though the scope of the outage — national or international — was unclear.

Facebook briefly went down on Thursday, though it did not immediately cite a cause for that outage.

Predictably, Twitter was full of discussion.