Getting Customers to 'Check In' With Foursquare

Getting Customers to 'Check In' With Foursquare
By RIVA RICHMOND
August 4, 2010
Wall Street Journal

Small-business owners try the latest free marketing tools: location-based social networks such as Foursquare, Brightkite, Gowalla, Loopt, Whrrl and review heavyweight Yelp.