I agree with coldtea. Our consumerison is why it we get isolated. What is intresting, tendencys in DE show that people go back in the cities for shopping (it's more socializing).
http://www.presseportal.de/pm/8664/2804458/innenstadt-bleibt...
Maybe when our kids getting in adolescence find that this is the way to be diffrent than us.
Good Practise:
Start greeting people when you are in your neighbourhood. That's what I did. I got very fast in contact with above-, below my floor and people around in that block. We had big times (even with the very old folks!). Friendliness and courage (to do so) is the key to start a relationship. The cause of the problem is our missing culture (even neighbourhood parties) to get connectd.
g start flash-mobs!