comScore, Inc. (NASDAQ: SCOR), a leader in measuring the digital world, today released the results of a study using its comScore Segment Metrix tool, which showed that heavy U.S. visitors to social networking sites are significantly more likely than average to visit leisure-oriented retail site categories, such as music, jewelry/luxury goods/accessories, consumer electronics and apparel. Heavy social networking visitors are defined as the top 20 percent of visitors based on time spent on social networking sites.