They're addressing the fact that there is a lot of artwork out there to which the artist is "anonymous". They want to make this orphaned artwork available for distribution and public use. But as a result, the bill will force the registration by an artist in order for the work to be ideally copyrighted.
Here's an interview of Brain Holland (a famous illustrator) with some information:
http://www.sellyourtvconceptnow.com/...nformation.mp3