Copyright Alliance has a useful FAQ that collects a number of questions and answers about copyright.

Works created after March 1, 1989 do not require a copyright notice in order to be protected under U.S. copyright law.  However, there are a number of benefits to including a copyright notice, such as:

1. It puts potential users on notice that copyright is claimed in the work.
2. In the case of a published work, a notice may prevent a defendant in a copyright infringement action from attempting to limit his or her liability for actual or statutory damages based on the “innocent infringement” defense.
3. It typically identifies the copyright owner at the time the work was first published, which may be useful for parties seeking permission to use the work.
4. It typically identifies the year of first publication, which may assist in the determination of the term of copyright protection in the case of an anonymous work, a pseudonymous work, or a work made for hire.
5. It may assist in preventing the work from becoming an “orphan work” by identifying the copyright owner.

For an in-depth discussion about how to properly include a copyright notice on your work, please see Compendium (Third) Chapter 2200.

– Rob Kasunic, Director of Registration Policy and Practices at the United States Copyright Office

Be sure to bookmark the Copyright Alliance “Copyright Q&A”