Single Player vs. Multi - any storyline differences?

[swirly]

There is no single player in D3. The best you can do is a private game, but it's still online, and the only difference is that no one else can join it.

Isn't that pretty much how it was in D2 as well? I mean... there was offline play, but the game itself was the same whether you played alone or with friends. Only the difficulty/drops/etc changed. So it is less that there is no single player and more that single player and multiplayer are simply the same game. Am I remembering something wrong or not aware of something with the new game?