From the New York Times Business Section, May 31, 2007
http://www.nytimes.com/2007/05/31/business/31scene.html
Copyrights That No One Knows About Don’t Help Anyone
By Hal Varian
May 31, 2007
Here’s a quiz question for authors: To copyright a written work in the United States, you must (a) register it with the Copyright Office; (b) insert a notice that says “Copyright © 2007”; (c) insert a notice that says “All rights reserved.”
Answer: none of the above. Under current law, a work is automatically copyrighted the moment it is “fixed in tangible form.” And these days, that copyright lasts virtually forever: 70 years after the death of the author, in most cases.
Since there is no requirement to register a work and a copyright lasts so long, the legal owner of a work can be difficult to find, particularly when the work is more than a few decades old.