A notice of copyright ownership, although not required, should appear on works for which a creator is claiming copyright ownership. Publication without notice may permit an innocent infringer defense. Nonetheless, because notice no longer is mandatory for copyright ownership, one should not assume that a work without a notice can be copied. To prevail in a copyright infringement action, a copyright owner must demonstrate ownership in a valid copyright and an unauthorized copying of the original elements of the work. A copyright owner can prove his or her work was copied by demonstrating an alleged infringer had access to the copyright owner's work and that the works are similar enough to support an inference the alleged infringer copied the work.
Similarity can be both literal and nonliteral.
Literal similarity focuses upon copying of direct quotations or close paraphrasing. Although copyright automatically inheres at the moment it is created without regard to whether the copyright ever is registered, registration is required to initiate an action for copyright infringement. A certificate of registration constitutes prima facie evidence of the validity of a copyright and of the facts stated in the certificate. Whether filing an application for registration is sufficient to support the initial filing of a claim of infringement is not clear. Some courts have held that an action for infringement cannot be asserted unless the certificate of registration has been issued.