Dave, I see some sites with and some sites without a copyright line. Do you know if someone must follow an official process before adding this line? Such as (C) 2002-2004 by Dave Taylor, etc...

In general, copyright law is defined by the international Berne Convention for the Protection of Literary and Artistic Works, which covers written materials, photography, illustrations, sketches, etc., but doesn't cover "news of the day or to miscellaneous facts having the character of mere items of press information".

A few important points from the Berne Convention: Copyright lasts for the life of the author and fifty years after his or her death. There's also Fair Use, which allows for (in typically vague legal wording) "quotations from a work which has already been lawfully made available to the public, providing that their making is compatible with fair practice".

Here's the most important paragraph in this long international agreement though: "In order that the author of a literary or artistic work protected by this Convention shall, in the absence of proof to the contrary, be regarded as such, and consequently be entitled to institute infringement proceedings in the countries of the Union, it shall be sufficient for his name to appear on the work in the usual manner." [ref]

This means that you do not need to have an explicit copyright notice for you to have a legally enforceable copyright, as long as your name appears on the work as an author. Anonymous material is covered too, but you can read about that yourself if you're interested.

The US Copyright Office clarifies how the Berne Convention applies to U.S. Copyright law: "The use of a copyright notice is no longer required under U.S. law, although it is often beneficial."

Continuing to quote from the Copyright Office: "Use of the notice may be important because it informs the public that the 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