The patch that adds Icecrown citadel will add a new three-wing five-man dungeon with a quest line that requires that you do them in order the first time through. Patch 3.3 will also add a cross-server LFG tool, meaning that you'll be able to form a 5-man group and enter a dungeon with them even though they're not on the same server.

I'm sure some people can conjure up some spectacular ninja scenarios from that, but it seems like an interesting technology. They said they'll be able to use it for raids if they want to, as well.