Last night, Facebook and its sister social media apps, Instagram and WhatsApp, went down for a period of seven hours.
Facebook has since issued a statement claiming a "faulty configuration change" on its routers was believed to be at the centre of the outage.
In statement, the company said: "Our engineering teams have learned that configuration changes on the backbone routers that coordinate network traffic between our data centres caused issues that interrupted this communication.
"This disruption to network traffic had a cascading effect on the way our data centres communicate, bringing our services to a halt."
But what does all this mean in simple terms?
Read more: Bonnie Tyler's response to Facebook going down is the best thing you'll see today
The explanation
The Guardian's technology editor, Alex Hern has explained what this means in layman's terms via a thread on Twitter.
He said: 'Facebook (accidentally, we assume) sent an update to a deep-level routing protocol on the internet that said, basically, "hey we don't have any servers any more xoxo'.
"Normally, this would be quite easy to fix. you just send another update saying "oh, don't worry, we have servers, they're here, xoxo". Things still break, it takes a while for the message to spread to all corners of the internet, egg on face, but liveable.
"But Facebook runs EVERYTHING through Facebook.
"So when its servers were booted off the internet, it also booted of the ability to send that follow-up message...
"And the ability to log-in to the system that would send the follow-up message...
"And the ability to use the smartcard door lock on the front door to the building that contains the servers that control the system that sends the follow-up message...
"And the messaging service you use to contact the head of physical security to tell them they need to high-tail it to the data centre out east with a physical key to override the smartcard door lock on the front door."
Essentially, Facebook removed itself from the internet, as well as its ability to put itself back on the internet.
Why did Instagram and Whatsapp also go down?
As Alex explained, Facebook uses its own systems to run everything - including Instagram and WhatsApp.
Until Facebook was able to resolve the issue, every one of its partner sites remained inaccessible.
How did Facebook resolve the issue?
Facebook so far have been very vague about what caused the issue and how they went about rectifying it.
However, there have been several reports that the tech giant sent a team of engineers to their server site in California to manually reset the servers.
Facebook systems have been up and running as normal today (October 5) and experts have assured us that events like this are fairly uncommon, so we can continue living our lives on social media as normal.
