Google Research Blog: [In May 2013] at Google I/O, we showed a major upgrade to the photos experience: you can now easily search your own photos without having to manually label each and every one of them. This is powered by computer vision and machine learning technology, which uses the visual content of an image to generate searchable tags for photos combined with other sources like text tags and EXIF metadata to enable search across thousands of concepts like a flower, food, car, jet ski, or turtle.”