This may be one of only a few problems I've heard concerning the PS3's hardware.  I knew that turning it off from the back was probably one of the best ways to mess it up, since it is just like a comp.  I have a really "smart" friend who came over to my house. I made him an account and started buying/dling stuff I didn't have yet to his account. He got mad because I was wasting money. He refused to believe that it would go over to my other accounts, and when I wouldn't stop doing it, he turned it off from the back.  It made me question his intelligence...

My PS3 seemed to be slower and freeze randomly a few times after that, but it seems to have gotten slightly better.  It still freezes at certain points.  When will people realize it is basically like a hard reboot on a desktop computer?