@iano made an interesting point: the lack of 4G in NYC is holding back app developers because less data hampers activity and word-of-mouth growth.
The Foursquare app is wickedly fast but it still takes me 5 seconds to check-in because of 3G. And if someone tells me about an awesome app over a cab ride, I can't quickly download it to check it out.
Everyone here is building (or has built) iOS apps in NYC, so I'm curious to hear your thoughts!
Also, free free to invite others who might have a unique perspective.