Facebook has gone offline today at approximately 8.30 GMT. A 'service unavailable' notice is currently displayed on the website.

With over 1 billion internet users logged on to Facebook daily, it's rare to see the site take a hit, but it is not yet clear what has caused the sudden outage or whether there is an issue with local servers in different regions.

Websites like Linkedin and Facebook depend on cloud servers and multiple datacenters to provide service to international users. Different technical factors can disrupt a user's ability to log on to the site. These reasons include server outages, power cuts, and DDoS attacks that overload servers.

Other possibilities include DNS errors and update problems when certain customizations are rolled out.

FACEBOOK IS DOWN! SERVICE UNAVAILABLE!

— Chris Ashby (@BWebChris) November 3, 2014

Facebook is down or it's just me?

— Recklezz (@recklezzmusic) November 3, 2014

This #alexfromtarget thing is probably the most ridiculous internet thing. Oh yeah, And Facebook is down.

— Ian L (@MyNameIsIan) November 3, 2014

My Facebook is down

UPDATE: Facebook access restored to a majority of users at 8.45pm GMT