For those at the University of Minnesota, the following announcement from the Libraries' listserv might be of interest:
Through November 30th, the Libraries have a trial for Footnote, a primary source database that spans American history from the Revolution to present. A large piece of their collection includes documents from the National Archives which are only available through Footnote. In addition, the database has an user interaction part where users can add their own primary sources, comment on documents already added, and work with other researchers interested in the same documents. Just go to http://www.footnote.com to try it out!