Interesting interview over at Gamasutra.
My favorite points:
Lego Pieces often have twice the polygons of a WoW Model.
Sharing your custom built area with the public requires human approval.
And this quote, "You should be able to hop in, have fun, play on your property for a while, build something, oh maybe you don't have enough bricks for the idea you have, so you'll play the game some more, get some leaderboard stuff going with some of the minigames with your friends, a little bit of fun, indirect competition going on, do a little co-op, go back to your property, build some stuff, go to your friends property, give them some models to help them build their property up -- that's more of the loop we're going for. Your own creativity is driving the depth you will get out of the game."
Check out the interview. Very awesome.