Over 700 comments were received during the inquiry period for comments by the Copyright Office on the topic of “orphaned works”: works whose copyright holders are either impossible or very difficult to find.
Currently, orphaned works are held in limbo: their creators (even if determined) cannot be located, so their works are in limbo, perhaps for forever, given the willingness of Congress to extend copyright terms. There seems to be some consensus that this is undesireable, and some push to allow a mechanism which allows such orphaned works to enter the world of the publically exploitable works.
I’ve surveyed only a couple of these comments. They seem very good. Check ’em out.