so I saw this article on digg and I must say it's pretty shitty. My guess is that Billy and the gang were sitting around in the studio one day with a bunch of shitty tracks going:

Billy: So, what are we going to do with these extra tracks?
Jimmy Chamberlin (drummer): What do you mean man, we're going to put them on the record, right?
Billy: Well, yeah, I would, but they're kind of shitty. This is going to be our first release in a 7 years, I don't want a few songs to reflect poorly upon the new album. Anyway, 15 songs is too much for a record.
Jimmy: Well I think they're good, maybe we can release them as B-sides or something? We DID go through all the trouble of getting them recorded and mastered.
Marketing Guy #1: Hey! I just got a great idea. Why don't we release them exclusively on iTunes. Then we can generate market buzz AND make money at the same time.
Billy: Hey yeah! Or maybe we can put them at the end of an album sort of like what they do with outtakes on Greatest Hits and stuff these days. I mean, everyone knows those songs were shit but market them as unreleased greats and all of a sudden people go ape shit over them!
Marketing Guy #1: Great idea. So we'll have maybe 3 special edition versions, each one with a different song that we shouldn't have released in the first place. I'll get on the line with Apple, Target, and Best Buy right away.
Billy: Awesome! *high five*

So, yeah. Don't complain TOO much Paul Thompson of pitchfork media. Those three extra tracks are probably shit anyway. And even if they aren't, you can always download them. I mean, it's illegal, but is it really unethical? IANAL, but you did PAY for the album, and really only got 4/5ths of the session. If I were you I'd go recover the rest from the internets.