Facebook has been up again for almost an hour now. I have noticed it has been down from at least 6 am until approximately 9 am. It is not common for such a big media site to completely go down. They have the funds and knowledge to have numerous backup servers in case something goes wrong.
Until now Facebook has not made any statements about the cause of the downtime. I bet there were a lot of frustrated people around the world not able to check their daily 'news'. Not to mention the advertising income Facebook lost today.
The site is up but I sense some glitches and now and then it is not connecting properly. Hoping they will fix it soon!