From 2000 to 2010 the supply of new housing units outpaced demand by 50 percent in the four largest metro Atlanta counties (Fulton, Gwinnett, DeKalb and Cobb), according to new census figures. The result: In those four counties alone, more than 143,000 houses, condos, apartments and other units were vacant in 2010 – and 67,000, or nearly half, of them were for rent. Find out what that means for renters, landlords and neighborhoods.