I thought the point of the internet is that it removes, to an extent, the friction of distance, meaning that the circles you move in may not be local to you. In the past, if I wanted to chat about politics I would have to do it with someone local or someone face to face. The postal service removed some of that friction, and now there is far less friction than that.

I doubt your neighbours will know much about your politics unless they're your Facebook friends too, and why would you add your neighbours to Facebook when you can speak to them face to face? (and do you?)