Libraries seem to be catching onto the fact that Flickr has become the de facto site for photo sharing on the web. It’s certainly not the only photo sharing site, but if your goal is to reach a large audience with well-organized and sharable images, Flickr is hard to beat.
The Library of Congress has been on Flickr since January, and has uploaded 3,815 photos to date. Just a sliver of their catalog, but a great start with images like the 1913 presidential inauguration of Woodrow Wilson:
Another interesting use is the San Mateo Library, which is publishing photos of speakers and other guests to Flickr including “The Bat Lady” who had her audience at attention as she taught children about bats: