A mere one billion, you scoff. YouAppi tracks content consumption on two billion people across 4,200 apps and mobile sites. It uses the data to target in-app, on-site, and social advertising for mobile app customer acquisition and retention. The company just launched a “360 Degree Growth Marketing Platform”, which is an extension of its earlier products. But we’re not talking self-service: YouAppi is a full-service agency, currently running almost 17,000 campaigns for 470 brands worldwide.