Look at Diablo 3. I am going to submit that you are all looking at the the newest record holder for most pirated game. Why? I'm glad you asked.
1. Persistent connection required. Lose your connection, and you can't play. Don't have an internet connection? You can't play. Yes, even the single player campaign. Why? See point 2.
2. Server side saves. All your save games are saved on the server side. Of course, ostensibly this is sold as a way to make you more mobile - go anywhere and have your saves! Oddly enough, I can take my current computer anywhere with Diablo and.... still have my saves. Wierd, huh? But wait! Their next excuse is that it cuts down the number of cheaters on battle net, because they can track your save games and watch for changes (like suddenly gaining too much gold, or having an item simply pop in when it shouldn't). Yet.... battlenet cheaters never bothered me, because Diablo 1 and Diablo 2 were both SINGLE PLAYER GAMES TOO! Lan and online was possible of course, but it wasn't necessarily the main game-play.
World of Warcraft has opened Blizzard's eyes to how they can milk people. Now they're destroying quite possibly one of the greatest most defining game franchises in history in order to make money.
I can already see the hacks. Change your host file to point from the authentication servers back to 127.0.0.1. Run an authentication hack on your computer, just like some of the new office versions, photoshop, or solid works requires. Game, while keeping your saves on your own computer.
I do not condone piracy. However, I own a game when I buy it. I can still play Diablo 1, and I still enjoy it. What happens when that authentication server goes away? My game is unplayable.
No thanks Blizzard.