Here's an interesting use of Web2.0's "architecture of participation" by the Library of Congress at Flickr...and lot's of beautiful photos without copyright restrictions!
(excerpt)...."the launch of a brand-new pilot project the Library of Congress is undertaking with Flickr, the enormously popular photo-sharing site that has been a Web 2.0 innovator. If all goes according to plan, the project will help address at least two major challenges: how to ensure better and better access to our collections, and how to ensure that we have the best possible information about those collections for the benefit of researchers and posterity. In many senses, we are looking to enhance our metadata (one of those Web 2.0 buzzwords that 90 percent of our readers could probably explain better than me).
The project is beginning somewhat modestly, but we hope to learn a lot from it. Out of some 14 million prints, photographs and other visual materials at the Library of Congress, more than 3,000 photos from two of our most popular collections are being made available on our new Flickr page, to include only images for which no copyright restrictions are known to exist.
The real magic comes when the power of the Flickr community takes over. We want people to tag, comment and make notes on the images, just like any other Flickr photo, which will benefit not only the community but also the collections themselves. For instance, many photos are missing key caption information such as where the photo was taken and who is pictured. If such information is collected via Flickr members, it can potentially enhance the quality of the bibliographic records for the images."