Now this is just my observations. Feel free to correct me. Also, if you are in another part of the US (i.e. Mid-west, West Coast, etc) let me know your observations on how local search marketing is being used in your area(s).

My thoughts are broken down like this: North vs South and large vs small vs inner city.

Disclaimer: I was born in NYC and grew up out the City but I live in Georgia now.  Ok.

North vs South
Local search is still in its early days so I understand why there are differences. Right now it appears that in general, the North (i.e. mid-Atlantic, New England) states are using local search a lot more than the South.  During my travels and local surfing, I found a lot  more businesses took the time to add their own business profile (rather than have Google etc, fill it in).  I also saw more reviews of businesses on-line and much more advertising of web sites or local directories.

In the South, I see less businesses putting their info on-line, less customers creating on-line reviews, and small businesses not having much if any web presence.  I know here in Augusta, GA, local search as well as Internet marketing has not yet peaked.

City Size
Now the larger cities are definitely using local search more than smaller cities, while many of the inner city businesses are not.  I was in a pretty rough part of Baltimore, visiting a pastor of a local church, on my trip. The businesses I saw there, were simply trying to survive-Internet Marketing was far from their minds.

Augusta is the third largest city in Georgia but Internet marketing as I said is no where near Atlanta, Athens, or Savannah.

My observations raised the question in my mind: Will local search ever be fully used throughout the entire US? Right now I would say no. Cities and businesses in the South definitely will be using local search more as the Internet grows.  The smaller cities and towns and even the inner cities will also use it more too, but will probably never reach the same level as those in the big cities due to size and needs.