Full disclosure: all of the Digg editors currently reside in New York. If you'd asked us how many distinct neighborhoods we could name among all its boroughs, we might have come up with a whole lot… but not, like, 288-a lot.
A Reddit user created this interactive map that defines every little pockets of the entire city. And it is impressive.
There are a few interesting omissions: this map doesn't count Hamilton Heights as a neighborhood of the island of Manhattan, though many realtors market the part of west Harlem above 145th street or so as such. Nor does this Redditor distinguish RAMBO (an acronym for the very specific area "Right Around the Manhattan Bridge Overpass") from broader Downtown Brooklyn.
So there's certainly some subjective judgment at work here. Still, this is probably the most complex visualization of New York's neighborhoods we've ever seen.