Downdetector, a site that tracks network outages on popular online services, said it was the biggest disruption it had ever witnessed.
"By duration, this is by far the largest outage we have seen since the launch of Downdetector in 2012," Downdetector co-founder Tom Sanders said in a statement.
"Our systems processed about 7.5 million problem reports from end users over the course of this incident. Never before have we such a large-scale outage."
Despite initial conspiracy theories that hackers were to blame, the reality seems far more benign.
Early the next morning, Facebook blamed the fiasco on problems arising from a change in its servers.
"Yesterday, as a result of a server configuration change, many people had trouble accessing our apps and services," the company posted on Twitter.
"We've now resolved the issues and our systems are recovering. We're very sorry for the inconvenience and appreciate everyone's patience."
As the chaos unfolded over on Twitter, the company was quick to reject speculation the problem was the result of a denial-of-service attack — a type of cyberattack that overloads the host of a service with superfluous requests.
Facebook's problems came the day after Google experienced major issues with its services including Google Drive and Gmail, causing many workplaces to grind to a halt.
It's a reminder of how utterly dependent we are on the digital stalwarts of Silicon Valley and could add fuel to the fire in the ongoing debate about whether they should be broken up.
A former senior Facebook employee, senior US politicians including presidential candidate Elizabeth Warren and major media companies including News Corp Australia, the publisher of this website, have advocated for Google and Facebook to be broken up due to their stranglehold on the delivery of digital news and online ad revenue.
