StumbleUpon is a personalized recommendation engine that finds and recommends websites, pictures and videos to users based on topics they choose. The document outlines how bloggers can use StumbleUpon to generate targeted traffic to their blog by installing the StumbleUpon add-on, thumbing up their blog posts, adding relevant tags, and sending posts to friends on the platform. The more thumbs up a post receives, the more StumbleUpon users will see and discover the blog.