The latest iPods have a cryptographic "checksum" in their song databases that prevents third-party applications from synching with the portable music players. This means that iPods can no longer be used with operating systems where iTunes doesn't exist -- like Linux, where gtkpod and Amarok are common free tools used by iPod owners to load their players.
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The new hardware limits the number of potential customers for Apple's products, adding engineering cost to a device in order to reduce its functionality. It's hard to understand why Apple would do this, but the most likely explanations are that Apple wants to be sure that competitors can't build their own players to load up iPods -- now that half of the major labels have gone DRM free, it's conceivable that we'd get a Rhapsody or Amazon player that automatically loaded the non-DRM tracks they sold you on your iPod (again, note that this has nothing to do with preventing piracy -- this is about preventing competition with the iTunes Store).
It won't be the first time Apple has rejigged iTunes/iPod to lock out competitors: back when Real built a DRM player for its own music that would run on an iPod, Apple threatened to sue them and engineered a firmware update to break their code (again, nothing to do with fighting piracy). This is the soul of anti-competitiveness: Real made code that iPod owners could use to get more legal use out of their iPods, Apple threatened to sue them for endangering their monopoly over delivering iPod software.