Big Worlds: Blogging in the ElderSphere

I read Jen Huget's interesting Blogging Through The Ages in the Washington Post recently, and couldn't help wondering whether there is a "big world" aspect of the medium that has to some extent been overlooked.

So are Elders one example of a Big World -- a really, really big world?  Elders are not exactly a small demographic, and are the wealthiest (at least in Western countries), and in some respects are more-connected that other segments.  Yet works like Mark Buchanan's Nexus: Small Worlds and the Groundbreaking Science of Networks has been taken to mean that people will be connecting in ever-more-refined groups.  Not sure if we're missing things with that model.  Oh maybe this is just a straw figure argument.