It's always a little worrying when you see developers and marketers working at crossed purposes. On the back of the box, at the top of the series of captioned pictures describing Anno: Create A New World's prime features, it says, "Team up with a friend and explore together".
Which sounds very nice, and very Wii-co-operative-social-play-stuff, but as far as I can see, it isn't mentioned in the manual. It doesn't appear to be mentioned at any point in the game, either. After playing my way through the story mode, I figured I'd just plug in a second controller and see what happened. Up comes a second pointer, which doesn't seem to be able to do anything functional in the game. You can send fireworks and put decorative things on the floor - which the other player can get rid of without even reaching for the delete tool - but nowt else.
While it doesn't actually contradict the back of the box, and the fireworks are pretty, it's only little more interaction than getting your friend to crouch beside your television and point with their fleshy finger to anything at which they think you should be having a nose.