Many people initially assumed that the company had been hacked. However as the outage continued there were none of the telltale signs of an attack. The outage impacted all of Facebook's tools and not just the site itself which made an attack increasingly unlikely. Even Instagram wasn't working. Thus the whole of the internet was left guessing.
Facebook engineers of course were busy working behind the scenes tracking the issue down. It has now been corrected. Facebook is up and running again and the company has concluded their investigation into the matter.
Here's the official word from the company:
"Our engineering teams have learned that configuration changes on the backbone routers that coordinate network traffic between our data centers caused issues that interrupted this communication.
This disruption to network traffic had a cascading effect on the way our data centers communicate, bringing our services to a halt. The underlying cause of this outage also impacted many of the internal tools and systems we use in our day-to-day operations, complicating our attempts to quickly diagnose and resolve the problem."
The outage couldn't have come at a worse time. Facebook is under increasing pressure from Congress to increase transparency. Naturally when the outage occurred conspiracy theories were rampant that the company was busily deleting files or otherwise destroying evidence.
Few of these were taken seriously of course but rumors tend to fly when no immediate explanation is forthcoming. This event was no exception.
In any case the issue is now resolved. So if Facebook plays an integral role in the conduct of your business you should be just fine at this point. Kudos to Facebook for the relatively rapid resolution.