The latest rumors to hit the net about Playstation are talking about the PS3 games getting serial numbers, i.e. computer games. Supposedly this is a response to fail0verflow cracking the console's root key.
This is type of anti-piracy measures tend to hurt legitimate players more than it hurts pirates. Serial keys have never worked, not on PC and I doubt it'll change on consoles. The only way this could even possibly work would be on multiplayer games. Some publishers are already a step ahead of Sony on that front. THQ for instance, is withholding online play for people who buy the game second hand unless they pay THQ for their code.
It will be interesting to see how far Sony is willing to take it and how it'll impact the lending of games from friend to friend, the used game market, and game rentals like Gamefly.
tl;dr: screw Sony's serial number idea