Is it Really Copyrighted?

Everything that is copyrightable is not necessarily copyrighted.

In some instances organizations and individuals choose not to copyright their work in order to encourage duplication and distribution. Before 1976, copyrighted works had to be registered and were required to carry a copyright notice. Lack of a copyright notice indicated lack of copyright protection. A work published without registration or without proper copyright notice automatically entered the public domain.  (Note: Due to treaty agreements, works published outside the United States that would have fallen under this may have have had their copyright restored and may be protected.)

These requirements have been eliminated. Registration was made optional in 1976 and, starting in March 1989, Congress dropped the notice requirement. Absence of copyright notice is no longer a reliable indicator of whether a work is protected.