Instead of selfies and status updates, many Facebook users got an error message during the outage that said: "Sorry, Something went wrong. We're working on getting this fixed as fast as we can."
The lengthy disruption is likely to upset advertisers that spend large amounts of money to reach potential customers on Facebook platforms. The company's flagship social network has more than 2.3 billion users, and Instagram has more than 1 billion.
People went on Twitter to vent their frustration about the problems. The hashtag #FacebookDown and #InstagramDown were trending on Twitter for much of the day.
People used the tags to post memes about the outage, speculate about its cause and trade tips for how to survive without the company's apps. Twitter even made the subject into a Twitter Moment.
"We're aware that some people are currently having trouble accessing the Facebook family of apps. We're working to resolve the issue as soon as possible," Facebook tweeted around 2 p.m. ET.
Despite some early online rumors that the outages were the result of a distributed denial-of-service (DDos) attack — a type of hack in which attackers flood a company's network — Facebook said in another tweet that "the issue is not related to a DDoS attack."
That second tweet was posted around 3 p.m. ET. Beyond Instagram's tweet, Facebook has provided no further updates in the hours since then.