Why didn’t I play longer? That’s a good question. You see, the game requires an always-on Internet connection, and the servers seemed to set themselves on fire a few hours after I downloaded the beta, and this dumped me from the game. You not only need to be online to play, you need to connected to Blizzard at all times. So if your connection goes down, or if their servers crash, you can’t play. Not even single player.
Hands-on with the Diablo 3 beta: keep that Internet on!
Every time I get marginally excited and start thinking about Diablo III again, the “always connected to the Internet” bit comes up and reminds me why it’s a bad, bad idea.
Source: Ars Technica