The network effect of Flickr's social photography
On April 8, 2008, Powerhouse Museum based out of Sydney, Australia, released their publicly-held historical photographs for access on Flickr, becoming the first museum in the world to do so. Earlier on Jan 16, 2008, the Library of Congress had released over 3000 photos on Flickr. What is common between these two contributions was that the rare photographs were in the public domain - they had no known copyright and are therefore free to reuse by anybody in the world.