Using Google Maps For Demographics

"Thanks to Adrian Holovaty, 24, who overlayed Chicago Police Department crime statistics on a Google map, house-hunters in the Albany Park neighborhood can pinpoint all the sexual assaults in the district between May 19 and April 19 on a single map. With each crime marked by a virtual pushpin, Chicagoans can quickly learn what dangerous train stations, pool rooms and alleys to avoid.

...Home buyers can pinpoint the locations of houses in their price range at Cytadia.com. And renters can turn to Housingmaps.com, which melds the technologies of Craigslist and Google, to spot available housing in 29 cities including San Francisco, New York, Los Angeles and Chicago."