I was just as much a naysayer as Dave was when the service first came out (and for the record, I haven't used it all either), but apparently there are lots of people who do use Apple's "Complete My Album" service in iTunes -- the NYT says that it has become a prime selling tool, especially for bands and labels that pre-release singles from their album in a digital format. A whopping 52% of Lil Wayne's latest album sales on iTunes were sold through the "Complete My Album" feature. That means half the people who bought the album on iTunes had previously purchased one of the singles, and clicked through that way to buy the rest of their music.
And though neither Dave or I use "Complete My Album," that's a good sign for consumers, and a nice wake up call for the record industry -- the days of playing a song on the radio to up album sales are over. Digital releases are what sells music, and though "Complete My Album" currently only works on music previously purchased in the iTunes store, Apple could very easily extend that to all music in iTunes -- if you like a song that you've downloaded as a free single from the artist's website, it's just as easy to find music of theirs to buy in iTunes the same way.
We're done with a world where radio airplay determines what sells at the record store. These days, consumers are the ones who tell record makers what they want to buy -- it's already in their iTunes playlists.