Copyright is a form of protection provided by U.S. law to authors of "original works of authorship". When a work is published under the authority of the copyright owner, a notice of copyright may be placed on all publicly distributed copies or phonorecords. The use of the notice is the responsibility of the copyright owner and does not require permission from, or registration with, the Copyright Office.
Use of the notice informs the public that a work is protected by copyright, identifies the copyright owner, and shows the year of first publication. Furthermore, in the event that a work is infringed, if the work carries a proper notice, the court will not give any weight to a defendant's use of an innocent infringement defense—that is, to a claim that the defendant did not realize that the work was protected. An innocent infringement defense can result in a reduction in damages that the copyright owner would otherwise receive.
US law no longer requires the use of a copyright notice