When parents saw their children run outside to play, and productivity shot up at offices around the world, people knew something was wrong.
Yes, Facebook had gone down.
For a couple of hours Thursday, many of the social network's 550 million users found they could not view one another's wedding photos, share stories from TheOnion.com or chat about how bored they were. They couldn't even let their friends know, via Facebook, that Facebook was down.
During the outage, the company said it was "experiencing some site issues causing Facebook to be slow or unavailable for some users."
"We are working to resolve this issue as quickly as possible," a representative said in an e-mail.
The problems eased about two hours later, when Facebook said the issue had been resolved and it apologized for any inconvenience. But some users said they were still having problems Thursday afternoon.