Pinterest, which at four years old is still in its infancy compared to social sites such as Facebook and YouTube, is driving the greatest percentage of its traffic to retailers' sites, at 10.9 percent, according to the study. Facebook directs 5.3 percent of its traffic to shopping sites, YouTube 3.8 percent and Twitter 2.8 percent.
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"While search still dominates, social media is becoming a significant source of traffic across the Internet as consumers increasingly use sites like Facebook, Pinterest or YouTube more as discovery platforms," said Bill Tancer, general manager of global research for Experian Marketing Services.
Amazon is benefiting most from the growing social trend, ranking as the most popular retail site in traffic referrals from Facebook, YouTube and Pinterest. Discount retailers Wal-Mart and Target, which last month announced a collaboration with the site, also made the list on all three sites. Rounding out the top five in Pinterest referrals were daily deals site Zulily and Nordstrom.