Facebook has been heralded as a great source of referral traffic. Twitter, too, is an easy way of getting out links to like-minded followers. However, the sites have been eclipsed by StumbleUpon as the main source of referral traffic from social media sites.
StatCounter released statistics showing that more than half of all referral traffic from top social sites comes from the "discovery engine." Statistics for 18 consecutive days earlier this month show that 50.27 percent of all traffic from a top 10 list of social sites came from StumbleUpon. Facebook came in second at less than 40 percent of referrals, and other sites like Twitter and Reddit trailed far behind, not even making it to the percentage double digits.
Mashable points out that though StumbleUpon has been growing rapidly as of late, the statistics are still hard to swallow. The site has 12 million users, compared to Facebook’s 750 million, so the sheer ability for that smaller group to be able to out-refer the larger user base is a bit perplexing. StumbleUpon did recently enjoy its 25 billionth StumbleUpon button click, so there certainly is basis for saying the site is increasing in referral influence.