MySpace, the world's most popular social networking website, has been shut down after a power outage.
Visitors to the website are greeted with a game of Pacman and a message saying the service hoped to be back up and running by 0400 PST (1200 BST).
An earlier message on the website said it was "undergoing maintenance" and pledged to be back within the hour.
MySpace, which lets users create a personalised homepage, has more than two million visitors each month.
There was no indication on the website as to what had caused the power outage at the data centre for the service.
A MySpace spokesman told BBC News: "The data centre that MySpace and other companies use to host their sites has suffered from a power failure.
"Its engineers are working to solve the problem, and we hope it will soon be up and running again. In the meantime we apologise to our users for any inconvenience caused."
The website was bought by Rupert Murdoch's News Corp for $580m last July after it proved to be a huge success with youth audiences online.
The closure of the service, albeit temporarily, will be a blow for News Corp and MySpace in such a competitive environment.
Bebo, one of MySpace's keenest rivals, has been catching MySpace in terms of audience numbers in recent months.
A number of MySpace users have posted comments on other blogging services - such as Live Journal and Wordpress - about the temporary closure of the site.
Vanessa Evans, sales and marketing manager at Internet infrastructure firm Linx, said companies typically took steps to ensure a power outage would not topple a website.
"Data centres usually have the ability to connect to at least two power sources so that they can switch in case one source is lost.
"I would be surprised for any large company taking space on a data centre which did not have this option."
Ms Evans said that while she could not comment on the MySpace problem directly, she said many companies hosted information at more than one data centre.