+Bob Calder+Chris Robinson Dont expect any immediate magic with communities. But they have a force multiplier effect and is a far more effective way to reach a "targeted" audience than the normal way of following and being followed. Communities represent the real interest graph and not the social graph of the generic platform. Here again there are two kinds of communities. Generic ones like this one where you will have a huge audience but have lots of noise versus more focused ones which are more difficult to grow but will pay off in the longer term.