Flickr’s Explore feature provides users with a quick look at photos that have been selected by Flickr for presentation to a wider audience. Many photographers would like to see their photos selected, obviously, to obtain a wider audience for their work.
How does Explore select photos? The specific details are not disclosed to avoid “gaming” the selection process. But there are hints in a 2006 U.S. Patent filing by Yahoo:
These rankings may be based at least in part on the quantity of user-entered metadata concerning the media object, the number of users who have assigned metadata to the media object, access patterns related to the media object, and/or a lapse of time related to the media object.
It appears to do with a “scoring” process that evaluates the “tags” assigned to a photo (e.g. “County Fair”, “Cow”), their relevance to the image, an “access pattern” (presumably an association between the searched for keywords that led to viewing the photo, and the tags assigned by the uploader), the number of click thrus and views of the photo, and the relationship of the viewer to the photographer (e.g. “friend”, stranger). There are likely other factors that go into this process (8 years after the patent was filed).