A MySpace spokesman has confirmed that the data centre that MySpace and some other companies use to host their sites has suffered from a power failure. MySpace also claim that engineers are working to solve the problem as soon as they can.
One does not generally expect a power outage to cripple a data centre. Such centres usually connect to at least two power sources so that they can switch in case one source fails. Additionally, failover is usually configured between two data centres with identical servers at each site so that disasters can be recovered from (even loosing an entire data centre through fire, flood, etc.) Most large companies employ these sorts of options in their data centres so it is surprising that MySpace is down at all.