Explore and that page has a subset called Flickr interestingness where they rank each photo's "interestingness" based on clickthroughs, links, favorites, tags, comments, and page views as far as I can tell. Very very cool. They also give each user a list of their Most interesting fotos. This one of the Grand Canyon is my most interesting photos, mostly from the six people who have favorited it. Watch out clicking those links, you are going to see some amazing photos.