I'm proficient enough to build my own computer and maintain it, but I know very little of programming and the act of hacking goes completly over my head. The attack on the Playstation Network has got me wondering about the hacking process.

How does one find out he has been hacked? In this case I suppose the user's account data was copied so it isn't as though something is missing, like if a bank is hacked and money is transferred. Effectively, in my eyes at least, someone came into the system and didn't change anything so there doesn't seem to be a discrepancy. So, how do you think Sony realized it was hacked? Did a regularly scheduled program tell Sony that someone unauthorized had accessed their files? Or, did a person examining log files simply notice a hiccup in the system? Seeing as how "nothing was stolen" I sort of have the idea in my head a person found out Sony was hacked rather than a program.

Also, hacking 101 I suppose; does one have to be physically connected to a Sony system to hack it or can any person access their files over the Internet (if they know how)?