[UPDATE 2] The PSN is back online.
[UPDATE]: Sony has posted the following statement to the PlayStation Blog:
"Like other major networks around the world, the PlayStation Network and Sony Entertainment Network have been impacted by an attempt to overwhelm our network with artificially high traffic.
Although this has impacted your ability to access our network and enjoy our services, no personal information has been accessed.
We will continue to work towards fixing this issue and hope to have our services up and running as soon as possible.
We regret any inconvenience this may have caused."
The original story is below:
If you're having trouble connecting to the PlayStation Network right now you're not alone. PlayStation's official support Twitter account has confirmed that PSN is working intermittently, and that Sony is working to fix the issue as soon as possible.
However, Sony said that there is no time frame at the moment for when service will resume as usual. It also said that some users are still able to log in to PSN or the PlayStation Store. I wasn't, and received the message that the service is currently undergoing maintenance. Note that this is not the maintenance time Sony scheduled for Monday, August 25, from 9:40 AM to 4:50 PM Pacific Time. PSN will be down during that period of time as well, during which Sony will deploy a series of back-end improvements to the network.
As first spotted by Shacknews, a group of hackers on Twitter has claimed responsibility for the disruption of service, saying they targeted PlayStation Network, Blizzard's Battle.net, League of Legends, and Path of Exile with denial-of-service attacks. DDoS attacks, as they're called, are usually carried out by bombarding a service or website with enough communications requests to make it unavailable to legitimate users.
GameSpot has reached out to Sony and will update this story with any new information we receive.