New York is not; it is just bigger, so the odds increase. But the show could be focused on any large or even medium-sized city.
I haven't watched the show yet, but I have studied and taught about social network theory. the "six degrees of separation" argument is somewhat based on random graph theory.
say six people each know 50 other people.
1 degree separation = 50 People
2 “ “ 50X50=2500
3 “ “ 50X50X50=125,000
4 “ “ 50X50X50X50=6,250,000
5 “ “ 50X50X50X50X50=312,500,000
6 “ “ 50X50X50X50X50X50=15,625,000,000
Obviously, this is more than six billion, so in theory it makes sense…but wait, what is wrong with our logic? Random graphs pay no attention to the physical proximity or similarity of the habits of the people involved. As a result, people who live on the same street are no more likely to be acquainted than eskimos and aborigines! In fact you would have more acquaintances in Russia than in your own town.
The point is.. People are not randomly wired up around the world. Therefore, the “clustering” of our social connections destroys the calculations we made for the random graph. Random universe does not support connectors
Each of you may know 50 people, and each of those 50 people may know an additional 50 people, but they probably won’t know 50 different people. There will be many overlaps and repeats and in fact, our social network will not grow as fast as our calculations indicated they would.
There has to be connections or "bridges" that tie networks together. For example, Joe has eight friends; and Sue has 12 friends. Joe doesn't know Sue. But Joe knows Sam, and Sue knows Sam. There is a connection linking the two (rather small) networks together. Sue is a "connector" in between the network.
Some connectors have LOTS of links; they are "well connected." For example, I don't know Charlie Egren. But I know Scott Grezckowski, and Scott knows Charlie. In fact, Scott knows LOTS of people in the satellite industry that I don't know. He would be would Malcom Gladwell would call a "maven." Or what we might call a "super node." I have my small network, which is connected into much larger networks. (Gladwell's book THE TIPPING POINT provides a good lay-person, non-scientific introduction to the concept of small worlds networks, but Duncan Watts book SIX DEGREES provides a much better, although far more academic one).
Or perhaps a better example. The internet: Millions (maybe billions) of computers connected through a TCP/IP network. Are all connections on the Internet the same? Of course not. My personal website gets a REALLY small amount of hits. But SatelliteGuys gets 40 million hits a month. It is a much bigger NODE on the network. Yet SatGuys is still small potatoes compared to Amazon.com or Google.com or Microsoft.com. Those are really big mavens.
Ok, I am going on an on. But one last thought. The term "six degrees" was popularized by the "Kevin Bacon game." Some college students came up with a game to see how connected the actor Kevin Bacon was within Hollywood. They found that almost every actor was within "six degrees" of separation from Kevin Bacon. For example. Patrick Stewart has a "Bacon number" of 2.
Patrick Stewart was in Let It Be Me (1995) with Campbell Scott (I)
Campbell Scott was in Loverboy (2005) with Kevin Bacon
Here's another: rosemarie dewitt has a Bacon number of 2.
Rosemarie DeWitt was in Cinderella Man (2005) with Beau Starr
Beau Starr was in Where the Truth Lies (2005) with Kevin Bacon.
The problem with the logic under the game, is that is assumes that there is something special about Kevin Bacon. There isn't. The reality is the entire network of actors is a really small group of people, and they are almost all highly related.
But I'll end with my personal favorite: I study Jun Fan Jeet Kune do under Troy Miller. Troy Miller studied it under Dan Innosanto. Dan studied under Bruce Lee. Therefore I am just two degrees of separation from Guro Dan Innosanto, and a mere three from Bruce Lee. Dang, I must be good.
EDIT: Play the Bacon game yourself - at
http://oracleofbacon.org/ See how many actors are beyond 2 or 3 degrees from Bacon.