Apple’s breaking out the Champagne over the 10 billionth song downloaded from iTunes, which turns out to be “Guess Things Happen That Way” by Johnny Cash. Yeah, mazel tov, Apple. Thing is, most of the media are reporting that Apple’s sold a billion songs, and that’s simply not the case. Why? Oh, just a little thing called digital-rights management, which was included with at least 3 billion of those songs.