Popular video sharing site YouTube was inaccessible to users this morning, displaying an 'Http/1.1 Service Unavailable' warning instead of the site's front page. Mirror sites, such as www.youtube.co.uk and www.youtube.com.au, were also closed for business.

Twitter was rapidly abuzz about the outage, which is reported to have started at around 7am GMT this morning. Sammyy_xx wrote, "I CAN'T LOAD THE YOUTUBE HOMEPAGE :O NOT GOOD." Other users were slightly more upset, such as Vegagirl5, who tweeted, "oh oh.... #Youtube is def down for the count !! #fail ..hmmmm..has this ever happened before ? this is very bad ...".

YouTube has recently upgraded it's network to support IPv6, a move intended to provide more Internet Protocol addresses, and reduce the need for workarounds like Network Address Translation (NAT). While the service as a whole has proved remarkably stable, even while increasing exponentially in popularity, malware writers have attempted to attack and subvert the site before, or use it as a channel to spread malicious programs to users.