Hi Mud Roy,
Trulia, Realtor, and other sites all use either Sq/Ft OR Sq/Ft AND Acres.
Sq/ft is common and preferred when looking at Residential Real Estate; to measure anything residential you'll need to measure it in Sq/Ft first, then convert that to a percent of Acres... it just doesn't make sense, unless it's more than an Acre; Acres are common with land sales.
Have you purchased a home, yourself? Can I ask why you prefer Acres of Sq/Ft?