Sony resetting some PSN passwords as a 'precautionary measure'

PSN users around the world have been booting up their various consoles only to be confronted with a message saying their passwords are incorrect. They've then had to go through the rigmarole of creating new login details, usually while still in the dark as to what happened to their accounts in the first place -- and whether they might have been hacked. Sony has since put out an explanation via various official channels in the US, EU and Japan, saying that only "some" users have been affected and that the password resets are "purely a precautionary measure" for "routine protection." We've contacted the company for clarification on its policy about contacting users individually in this sort of situation, and also to see if we can find out a little more about this "non-specific" threat to certain accounts.