Pinnability: Machine learning in the home feed
Pinterest hosts more than 30 billion Pins (and growing) with rich contextual and visual information. Tens of millions of Pinners (users) interact with the site every day by browsing, searching, Pinning, and clicking through to external sites. The home feed, a collection of Pins from the people, boards and interests followed, as well as recommendations including Picked for You, is the most heavily user-engaged part of the service, and contributes a large fraction of total repins. The more people Pin, the better Pinterest can get for each person, which puts us in a unique position to serve up inspiration as a discovery engine on an ongoing basis.