"We thought about this quite a bit," said executive producer Rob Pardo. "One of the things that we felt was really import 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."

"Now, that doesn’t mean you can’t play a game by yourself – of course you can," he added. "You can go into and start any game that you want, you’ll just be connected to the Battle.net servers, and we can authenticate your character."

In addition, Pardo revealed a list of Battle.net features that will be embedded in the game, requiring a constant Internet connection. These include: persistent friends list; cross-game chat via the RealID system; persistent characters that are stored server-side; persistent party system; player-versus-player and public game matchmaking; dynamic drop-in/out for co-op; larger item stash, shared among all of your characters; the auction house; achievements and detailed stat-tracking; the Banner system.

Now comes another shocker: no mods for Diablo 3. “For a variety of gameplay and security reasons, we will not be supporting bots or mods in Diablo 3, and they’ll be expressly prohibited by our terms of use for the game," read an official Diablo 3 FAQ handed out during the press event.

So no offline mode, no bots and no mods. 

I thought there was a thread about this out there already. However there is a simple solution to this that I figured out and the only downside really is the HDD space you will waste. Have one legal installation and one pirated one, and voila, you can now take D3 while you are abroad!

People like you causes piracy.

as long as you bought the game and have proof by either disc or reciept i do not think you even have to install the version you bought but just the piraed version and still be ok with in the eyes of the law.

Since I am basically always on the net anyways I will still get this game as I have been super excited for it for a long time. But seeing this is the path blizzard wants to go down it will most likely be the last purchase i make with them.