There is a very real threat to the public domain that started in 1998 when Congress passed the Sonny Bono Copyright Term Extension Act (CTEA). That Act extended the term of all existing copyrights by 20 years. But this was done without full realization of the effect of such legislation, and unnecessarily threatens the public domain and vintage films in general.
For example: The vast majority of film created during the 1920s and 1930s is not commercially available. Because of the CTEA, much of it remains under copyright. Yet because it is often impossible to track down the copyright owners for these films, commercial and noncommercial preservationist and distributors cannot safely restore and distribute these films. And because these films were made from nitrate-based stock, by the time the copyright to these films expire, most of them will have dissolved.
One solution in particular is being spearheaded by folks at the Public Domain Movie Database website. They are asking Congress to consider the Public Domain Enhancement Act. See http://eldred.cc This statute would require American copyright owners to pay a very low fee (for example, $1) fifty years after a copyrighted work was published. If the owner pays the fee, the copyright will continue for whatever duration Congress sets. But if the copyright is not worth even $1 to the owner, then they believe the work should pass into the public domain.
If you haven’t already, please go sign the Reclaim the Public Domain Petition — it only takes a few seconds of your time, is all done online, and is very easy. Momentum is starting to build, and they REALLY need everyone’s support.