"'Everyone wants to know now how close they are to stores,' says Linda Duggan, an owner of The Duggan Group real-estate agency. She recently had clients who, given a choice between a house in Danville, Calif., and another that was bigger, newer, $300,000 cheaper-and 20 minutes farther from town-chose the first one. Earlier this year Scott Newman, of Newman Realty in Chicago, started highlighting how close his listings are to amenities. The number of amenities in walking distance can vary sharply from block to block, he adds."
Real estate agents are trying to give prospective buyers a better idea about what sort of neighborhood they're buying with their house, and websites like Walk Score quantify walkability.