BizSugar.com › Marketing › StumbleUpon’s Steady Climb to Prominence

Despite the fact that it lags behind social media giants such as Facebook and Twitter in membership, with Facebook clocking in at over 900-million users and Twitter topping 140 million, StumbleUpon’s relatively small 25-million users are currently contributing more than 50 percent of all referral traffic from the web’s leading social media sites.