San Diego-based e-commerce firm ProFlowers.com was the top ranked U.S. web property for May, based on percentage change in unique visitors, according to the latest comScore Media Metrix numbers. According to comScore, Mother's Day, graduation, proms, and weddings helped to drive traffic to flower gift and greeting sites, driving ProFlowers to the top of the unique visitors increase list. ProFlowers.com, which is a unit of Provide Commerce, saw visitors grow from 2.7M uniques in April to 7.28M in May, a 168 percent increase. The ProFlowers site was second in terms of total unique visitors, behind AmericanGreetings, with 10.4 million visitors.