Sony aims at pirates and hits users: This is a good overview of the rootkit mess that Sony created with its DRM system.
This has been covered a lot else where, but the gist is that Sony put DRM on an album that hid itself on users’ hard drives and attempted to make itself invisible to anti-virus and anti-spyware systems.
Bummer for them that the guy who owns Winternals Software just happened to play the album on his machine and find the rootkit, which he then revealed to the world in geeky glory. (This is something akin to attempting to rob a bank and finding that God Himself was in line to deposit His paycheck at the same time.)
I don’t know the lasting impact this is going to have, but it’s drawn attention to an interesting issue and made Sony look like an idiot in the process.