What the City is Like
First of all, the game will be taking place in New York City - not the exact modern-day version of New York City that we know and love, but a slightly darker version.
Some obvious examples of how the "real world" New York City and the "game world" New York City differ:
The splitting point between the real world and the game world, in this instance, was the Tompkins Square Park Riot. It still happened - it just didn't create as much of anti-police backlash as it did in the real world. The covered-over badges, the police brutality, the rounding up of homeless; all of these things happened, but they didn't outrage as many people in the game world as they did in the real world. As a result, it's as if the area didn't get the shot in the arm that it did in the real world, so it remained seedy, run-down and dangerous. It's not a nice and friendly neighborhood.
(However, Times Square did get cleaned up and became a corporate "theme-park." That hasn't changed.)
Similarly, the anti-pornography movement that Mayor Giuliani started didn't work as well in the game world as it did in the real world. Sure, the City shut down a number of small places and XXX stores, but things like Show World and Peepland are still in the game, larger than life, competing with Disney for their little share of Times Square.... Also, non-Times Square XXX places are doing well - it's as if Giuliani wasn't able to pass the "500 foot" ruling that he did in the real world.
In fact, that might be a good way to think of the New York City of the Blood and Darkness Chronicle: it's a New York City that never moved out of the crime and degradation of the seventies and eighties. It's still dangerous, dark, seedy and can kill you in a minute - and that's just the mortal side of the equation!
There are other point-by-point moments where the game world and the real world differ, but for the most part, we can assume that the real world history of New York City is the game world history of New York City. There are a few changes, mostly in the area of urban renewal and yuppification (i.e., the Lower East Side and Williamsburg aren't the "hot new places" that they are now, there isn't a Starbucks™ on every corner, etc.).
Some Population Statistics (Mortal and Kindred)
Officially (i.e., according to the US Census), the in-game population of NYC is 9,214,000. However, this number does not include a good number of homeless, illegal immigrants, people who refused to answer the census, etc. The real number of people who reside in New York City is approximately 9,516,000 - a difference of 302,000 people! So, 9.5 million people reside in New York City, and a good 30% of those people reside in Manhattan (or around 2,854,800). The remaining 6,661,200 people are scattered between the outer boroughs. Of course, there are approximately 1.5 million people who commute to New York City (from New Jersey and Connecticut) for work, and an estimated 500,000 tourists in New York City during most of the year (according to NYC official statistics). So... Technically there is a population of approximately 11.5 million people, including around 2 million non-residential (their numbers fluctuate, depending on the season and day of the week) people.
For the longest time, there was a rough limit of 100 Kindred in New York City. Prince de Luca has recently removed the restraints on the exact number of Kindred in New York City, provided that "the population does not grow to unwieldy and poses a threat to the Masquerade." Prince de Luca (and Secretary Ford and Seneschal Guder) have stated that if the relaxing of limits does not allow people to ignore the Third Tradition - permission to sire Childe must still be obtained. Additionally, Prince de Luca has hinted that if her relaxation of the former limits poses problems, she will reinstate and rigorously enforce the previous limits.