The Library of Congress photographs, in the first 24 hours of being posted last January, received 11,000 tags - ways of categorizing and connecting the photographs. To Ms. Srivastava, the reflections from users about a photograph of dockworkers - discussions about segregation in America and changing work habits - are highly relevant to the project.
One frequent annotater of Library of Congress photographs of New York City on Flickr goes by the name Epicharmus. "I'm not sure I've 'discovered' anything so much as made connections between bits of information that are already public," he wrote in an e-mail message. The library's photos, he added, "have mysteries that seem to be beyond all solving - could there be any person alive that can correctly identify the location of this tenement or that factory wall?"