The live feed was kinda jacked up, but I did manage to get a few looks at the trailer and gameplay.
Some things to note:
It looked like the game is not an MMORPG. The guy was playing a barbarian at the time, doing a quest to rescue some dude, and it was not MMORPGish at all. It also kept the similar perspective as Diablo 1 and 2. I'm pretty sure that it's going to basically stick to the same format as Diablo 1 and 2 did.
There seemed to be a lot of gameplay for a game that was just announced. The game looked fully functional, at least for where they were and for what they were doing. The barbarian they were playing seemed to be pretty damn functional.
The game looks somewhat like it was done with a similar sort of engine as WC3, in my opinion, but I didn't see a ton.
Anyway, doesn't look like there's much info up right now, and since the live feed is busted, that's all I've got for now. I'll update later when they actually get the website set up and such.
For now you can see the really cool new splash screen at www.battle.net
See it. Lots of nifty info. The trailer and gamplay video are awesome.