Though this error has happened in the past (8001050F), but it had never happened on this scale, the outage seems to be worldwide, and affecting a huge majority of users. It’s causing people to lose trophy data, inability to access even single player games (like Heavy Rain) and causes some corrupted data. Jeff Rubenstein of SCEA has updated the public on the official blog stating:

We’re aware that many of you are having difficulty connecting to the PlayStation Network this evening. Those of you with “slim” PS3s (the 120/250 GB models) appear to be unaffected.

Know that we have narrowed down the issue and have engineers working to restore service even as you read this. We apologize for any inconvenience this may cause you, and genuinely appreciate your patience while we work to resolve this.

Is the not-affecting-slim deal accurate? I feel a lot of folks here have a Slim and are having the same problem, so it seems more universal than being isolated to the fat systems. Since they know what’s causing the issue, it should be back up in due time. One thing I definitely advise you to do, though, is not to attempt to play ANY games just in case the error irreversibly deletes all trophy data. Apparently other things affected are downloadables (DLC, movies etc), saying the content wasn’t purchased or something along those lines, so just to be on the safe side, don’t use your PS3 until the issue is resolved, even if you haven’t tried to see if you’ve gotten the errors.

Also, this site has been hit with heavy traffic, so you may get some Internal Server Errors, so to save up on some of the bandwidth, Tosh currently only has 1 post on the home page and I opted not to use an image on this to more effectively get the word out to our readers.

UPDATE:
This error is happening on non-connected PS3s as well, which means there’s something wrong with the firmware. People are calling it the Y2K10 or 02/28/2K10 bug, since it usually reverts the system clock back to 1999. For some reason, this affects almost everything else as well, and the only probable fix will be a firmware update. Some folks are thinking that the PS3 and the system clock want to recognize 2010 as a leap year, and the calendar says “no way dude, that’s not for a couple years”, and the conflict is causing the system to crap all over itself. I still advise to not even bother touching the system until the issue is resolved, though (manually setting the clock won’t work either).

And yeah, it’s confirmed the Slim systems are just fine. Sounds like a definite incompatibility issue with the firmware and the older models.