Several of the comments on my last post have been pursuing the connection between class and geographic mobility. And if we understand "class" as being about more than just income and education level, then yes: the perceived ability to move far away from where one grew up does correlate with class; it's about how many and what kinds of connections and opportunities one has.
If your college friends come from all over the country and then fan out to jobs and graduate programs all over the country once they leave, then you have a different sense of what's possible in your life (whether or not you personally choose to leave the city or state in which you grew up). Some of my students literally do not know anyone who lives more than a few hours away, and though our region does feel the gravitational pull of Boston and New York (their baseball and basketball teams are the ones locals here root for), the students who actually move to those cities after graduation--or indeed to any others, or who move out of this state--are almost exclusively those who already have family or friends there.
So in thinking about what it means to be rooted or rootless, I'm partly thinking about class. But one peculiarity of being an academic is that, unlike most people in "our class," we actually do up and move anywhere. The other people in our class? Not so much. They move to the coasts, basically, and in lesser numbers to places like Atlanta and Chicago, Austin and Houston, Minneapolis and Denver, and the bigger, wealthier college towns. I guess I had always known this, and it's certainly true of my college friends--but I still think of my class as figuring out their lives and as not having settled down yet. But at Cosimo's (ahem) 20th college reunion last summer, I realized that no one apart from the academics and a few quirky entrepreneurs lived anywhere but those places. I met person after person, waiting in line for the ladies room or making small talk at the bar, and they all lived in Fairfax or Fairfield County, or in Newton, MA, or in metro L.A. or S.F. And though they were all friendly and interested in who I was and what I did, they all seemed puzzled by where I lived. Like I said: it's not a place that people move to.
So my point, if I have one, is that even the class that seems to have infinite geographic mobility, doesn't. There are real restrictions on where, say, a high-powered corporate lawyer can have a career, and hence where he can live, but there are also cultural and class restrictions that operate to keep us where "our kind of people" live. If we're not living near our actual families (and of course I do know people who have moved back to their childhood homes), we're living near our families of affiliation: people with similar educations, professions, and interests. I'm not interested in criticizing that choice; indeed, if one can't or doesn't wish to go home again, it makes sense to choose one's new home based on the relationships one has or expects to build with the people there.
But those roots are relatively shallow, even for those who live in major metropolitan areas. And as Shane noted in his comment, those of us who live in more unlikely places often wind up doing a version of the same thing, which is to say, socializing primarily with other transplants. I have a few friends who are locals--former grad students, people I've met through arts organizations, or people I know from my church. But the people I'm closest friends with are others who moved here for jobs (mostly in academia or the medical sciences); some have put down roots here and some haven't, but none are likely to retire here. Sometimes I feel like a real local, or at least a civic booster and aspiring local; at other times I feel like I'm part of a community of expats.