In a recent post to her new blog, Elizabeth Townsend-Gard wonders about an unusual copyright provision concerning unpublished works and its impact on scholarship. The 1976 Copyright Act granted federal copyright for the first time to unpublished, unregistered works with the provision that these works would lose their perpetual common law copyright. They now enter the public domain using the same timeframe as published works. There are two twists: (1) No matter when the work was created, it enjoyed copyright at least until December 31, 2002. (2) If the work was published by December 31, 2002, the term of copyright does not expire before December 31, 2047. See Section 303.
It is a good question for investigation, but my take is no. Oh sure, the editor of the Mark Twain Project asserted in a post in 1998, in response to some comments from Siva Vaidhyanathan, that "that virtually everything now unpublished by Mark Twain will therefore *be* published before the end of 2001" in order to secure copyright protection. If such microfilms were ever produced and distributed to the public (the definition of publication in the law), though, I haven't seen notice of it. I can't think of any other effort to try to take advantage of the 2047 extension (though there must have been some).
As for changing scholarship, I don't think many historians and literary scholars were aware of the draconian restrictions on unpublished work prior to it receiving Federal copyright protection (unless they were working with relatively contemporary materials). That, at least, is the sense I get from Michael Les Benedict's excellent analysis of the pre- and post-copyright regimes in " "Historians and the Continuing Controversy over Fair Use of Unpublished Manuscript Materials" in the the American Historical Review 1986. If they didn't understand the rules before, I don't know if the looser restrictions now would change their behavior.
It will be interesting, however, to see if Elizabeth can prove my assumptions right or wrong.
UPDATE: the introductory paragraph was expanded to describe the law on 9/15/2004.