1) Globalization - the lessons learned and processes formed from globalization have in a sense come back to be applied domestically. Increasingly dominant corporations usually have numerous satellite offices to be able to tap the talent and resources throughout the country. For example if you are a Finance guy and you want to work for Google that doesn't mean you have to be working in the Mountain View office (I'd assume). Just about every city has a pretty diverse set of employment opportunities.
2) Increasingly Artificial Relationships - This one is very debatable but for a number of reasons (culture, technology, etc.) Id say that establishing light bonds with lots of people is incredibly easy these days but establishing a strong support network of friends is increasingly hard. I'd guess that due to this people will increasingly be incentivized to stay within the general vicinity of longtime friends and family rather than moving across the country with the risk of never being able to build and be surrounded by a network of "real" relationships. YMMV but I think its getting harder to find 3 new great "will pick you up when you're in the gutter" friends.
3) Similar to number 1 - the US geographically is becoming more the same than different in my opinion. There are certainly still differences but if you move to another state its highly likely that you will be surrounded by a mixture of city and suburbs that contain the same types of things just with different names. Probably mass media and the internet are responsible for this one.