As reported on Rock Paper Shotgun Diablo 3 creators Blizzard have announced:
1) The game requires a constant internet connection. It cannot be played offline.
2) Mods are “expressly prohibited.”
3) Items in the auction house are bought and sold for real-life money.
RPS is not impressed. The Blizzard justification for this is below.
1) “One of the things that we felt was really important was that if you did play offline, if we allowed for that experience, you’d start a character, you’d get him all the way to level 20 or level 30 or level 40 or what have you, and then at that point you might decide to want to venture onto Battle.net. But you’d have to start a character from scratch, because there’d be no way for us to guarantee no cheats were involved, if we let you play on the client and then take that character online.” Also, piracy.
3) “We think it’s really going to add a lot of depth to the game. If I have more money than time I can purchase items, or if I’m leet in the game I can get benefits out of it. The players really want it. This is something that we know people are going to do either way. We can provide them a really safe, awesome, fun experience, or they’ll find ways of doing it elsewhere.”