A colleague pointed out a blog to me about business closings in Columbia. The author posts pictures he has of businesses that no longer exist and visitors have the opportunity to comment on those pictures.
The Library of Congress does something similar on Flickr. They are posting pictures from their collection. Flickr visitors then have the opportunity to provide comments on the pics. The LOC has identified many people in the pictures from information provided by the comments.
It is such a unique way to make technology connect us with the past and to keep the past alive for the future. Too bad there wasn't something like a blog in 1910 or 1957 or anytime that we are looking for information about.