Apple Locking iPods To iTunes?
The modification more or less prevents using an 'updated' iPod with another program that would alter the playlist in any way, either deleting, adding, or possibly even changing the songs in any way (such as the bit-rate, order, etc.). If the iPod isn't exactly as iTunes remembered it, the iPod will inconveniently 'forget' all your songs:
“The most plausible reason for locking then new iPods to iTunes is that Apple is becoming conscious of the growing threat that other music services are offering. Since many music labels are dumping DRM, it is now easier than ever for music services like Rhapsody to load non-DRM music directly to iPods through its own player; meaning iTunes is taken out of the picture as the digital content handler for iPods.
Locking iPods to iTunes effectively inhibits other media players from handling content for iPods. This move also prevents other music services from truly competing with the iTunes store and maintains Apple’s dominance.”
Whether this is a conspiracy or a massive bug that somehow escaped the quality assurance team is unclear at this point and we're still waiting to hear what Apple has to say. We'll keep you up to date as this story continues to develop.