I’ve been asked before what this DRM thing is, or why they can’t listen to their music anymore. Well Mark gets asked to explain it to his dad and linked is the letter… To give you an idea on how well written this was, read this one paragraph that may just answer your question on what it does.

So what happens on August 31, 2008? On that day, Microsoft will turn off the servers that they maintain for the sole purpose of validating that the songs that people have already “purchased” through MSN Music are still theirs to play. Those people (hereafter “the victims”) will not notice the change right away. The victims will only notice it when they purchase a new computer, or when they upgrade the operating system on their current computer, or when the hard drive in their computer dies and needs to be rebuilt/reinstalled. At that point — transferring the music files they have “purchased” to another drive or a new computer — the Microsoft music player running on the victim’s PC (like iTunes, but all Microsoft-y instead of Apple-y) will make a call to Microsoft’s validation servers to verify that the music files were legitimately purchased. This call will fail, since the servers are not responding, since Microsoft has intentionally turned them off. The Microsoft music player will then conclude, incorrectly but steadfastly, that the music files were downloaded illegally and that the victim is a filthy pirate, and it will refuse to play them. In this case, the left hand knows exactly what the right hand is doing: they’re both giving you the finger.

[dive into mark talks about The day the music died ]

That said, I will note that Steve Job many times has said he’d rather sell the songs DRM free, but has been required to by the record companies.