Some of what Putnam reported was flawed, and his book that you cited was interpretative. These "actual mesasurements" that you speak of do not show that in-person social engagement has been in decline -- that is Putnam's interpretation of the data. Others have different interpretations (which I happen to agree with much more). For example, see http://www.theatlantic.com/past/docs/issues/96apr/kicking/ki....