I think people have always had a bias toward permanence.  In this college town it can be hard for people to put effort into making friends with people that you know are moving away.  Maybe it's in 6 months, or maybe it's years away, but since we're planning on staying, we want to have friends that will be here as long as we will.  The online world gives a certain persistence that transcends physical location, and that gives people a sense of comfort.  Besides, there are so many people who don't know (or don't want to know) their neighbors.  It's easier to go online and pick people whom you want to commune with than putting in the work to get along with neighbors you didn't choose.

I guess I'm Gen Y, so I have a hard time accepting stereotypes like this, but I do see a lot of other people around my age constantly focusing on text messages and Facebook status changes.  I think it's important that people find a community to be a part of, whether it's in your neighborhood, in your religious organization, or online.