Approximately a week ago the playstation network went down due to an outside influence (hackers). It is still currently down and the people at playstation are working on fixing this problem. I was watching the news and saw a report stating that the hackers may have got personal info from the PS3 user accounts (such as credit card info if you've ever purchased something from their online store with it). So it is highly suggested that you have your credit card canceled. If you'd like to read more into this story, read this link:

http://blog.us.playstation.com/2011/04/26/update-on-playstation-network-and-qriocity/