Daniel Gross in The New York Magazine:
The paradox of money in New York is that it is at once the universal topic of conversation and a taboo. Personal spending is the subject of both relentless boast and discretion. As a result, some basic concepts—what it takes to be rich in New York, how many superrich people there are in the city, and precisely how they affect the economy—are shrouded in mystery. But with the help of some reluctant economists, I’ve tried to make some (reasonably) educated guesses.