1. Tinder is a location-based dating app with 50 million users that matches people anonymously who swipe right on each other's profiles. 2. It was founded in 2012 and has had some leadership changes and a sexual harassment lawsuit, but now has Sean Rad back as CEO. 3. The app is monetized through Tinder Plus subscriptions and ads, and had $75 million in revenues in 2015, with reported valuations between $1.2-1.6 billion.