Flickr is a four year old online photosharing community. Before January of 2008, it primarily held ?user-generated content,? photographs and stories from individuals in practically every country on the planet. Pioneering a variety of ?Web 2.0? technologies like tagging, Flickr has grown into an enormous corpus of photography that reflects humanity over the last four years, and beyond. ?The Commons? is a program we've developed to introduce publicly-held photography collections into the mix. Releasing a pilot partnership with the Library of Congress Prints & Photographs Catalog has at once provided an interesting counterbalance to this ?user-generated? archive and also begun to test ideas around the knowledge, authority and participation of the general public. Primarily intended to increase access to the vast collections of photography held in libraries, archives and museums around the world, the program also seeks to gather additional context about objects in these collections, and potentially even feedback or be cross-referenced by those institutions participating. There are thousands of interested members of the general public already adding information and knowledge about the content released in the pilot program. This paper is intended to outline the progress of the pilot so far, and to provide information for interested parties about how to participate in the Commons on Flickr.