StumbleUpon has mastered the science of making money on mobile

Older than Facebook, 10-year-old Internet discovery engine StumbleUpon may also be wiser. The social web exploration company is growing fastest on mobile, but unlike behemoth social network Facebook, Stumbleupon has not-so-accidentally stumbled upon a formula for serving advertisements to mobile users in a way that doesn't jeopardize the bottom line.

http://pulse.me/s/bkanX