Rockstars
There are the ego type Rockstars, that gets their own isolated parts of the system, as nobody wantys to work with them. They are not really rockstars.
To me the Rockstar has a fanbase among the other developers, he is the one people comes to and asks for advice, and uses for sparring about new ideas. He is the one that will actually help the team as a whole, and communications is part of this. In a pure nerd group, comms is different than in a mixed skills group.