Apparently Apple has started inserting cryptographic checksums in the DB of music stored on iPods. This breaks 3rd party software for managing your iPod music library, tying the iPod to iTunes.
I’m sure there are a lot of bad reasons for implementing this, like keeping people from creating applications that let people share music directly between WiFi enabled iPod’s and iPhones.
I use iTunes, I own Apple stock, but really, this is complete customer hostile crap. Screw them.