Pinterest is focused on bettering it's search and discovery functionality to make it easier for people to find the things that they love.
A recent acquisition of a two-person company (former Google employees) called VisualGraph, a company which finds connections between images through things like face recognition, object recognition and shape/color analysis.
By improving search and auto-detecting relationships between images, Pinterest will be able to build more relevancy with it's app--making smart recommendations, finding patterns and supplement it's reliance on human categorization of images.