I liked the way Blizzard let you play it a bit differently every time by providing randomly generated maps. But I wonder how does it work?

In Diablo 2 online, it would have been insane to send all the randomly generated level data to the many players playing it. I'd imagine the server will only send a random number - sort of like a seed for the level generation algorithms, and basically let the players generate the level accordingly themselves.

Will love to hear any experience you've had playing with random level generation and your takes on the subject.