When users tried to open or refresh their Facebook pages a little after 12:30 p.m. ET today, they were greeted not with their news feed but with a largely blank screen that simply said, "Sorry, something went wrong. We're working on it and we'll get it fixed as soon as we can."
The site began to come back online around 12:50 p.m., though some users reported still having trouble loading the site until about 1 p.m.
Facebook did not return a request for information on what caused the problem.
The web site Downrightnow.com reported that Facebook, the world's largest social network, with 1.49 billion monthly active users, was likely suffering a service disruption.
Frustrated users quickly turned to Twitter to complain about the crash, during what would be lunch break time on the East Coast.
At least Little Caesars was quick to take advantage of the situation, tweeting, "With #facebookdown, make sure to KEEP CALM & STAY CHEESY and then step out and grab a $5 HOT-AND-READY LUNCH COMBO. ;-)"
And others just took the opportunity to have fun with it.
"Is everybody ok Did something happen Are the zombies attacking I'm scared!!! #facebookdown," tweeted @MootePoints.
And UK Banter tweeted, "How am I meant to judge the people I went to school with now #FacebookDown."