On Copyrighting

Brad at Feld Thoughts is wondering about copyrighting PowerPoint slides:

As I was sitting in the audience, I noticed one thing that kept annoying me. A number of the presentations said Copyright "SOMETHING_OTHER_THAN_2004" in the footer. I've noticed this a lot recently, as footers seems to have "Copyright 2002", "Copyright 11/02" or simply "4/12/03". You'd think that PowerPoint would have an autocorrect rule for "Copyright."

Perhaps a more pertinent question is why people use the copyright symbol or the word "copyright" at all. Copyright protection exists as soon as a work is created in fixed form, and copyright notice has not been required since 1989, though the perception of the need for such notice is widespread. Despite the lack of a notice requirement, the use of copyright notices is common as a means of alerting people about the intention of the work's owner to assert copyright protection. It also may have an evidentiary function, especially in cases where there is a claim of innocent infringement.

This is cross-posted on Venturpreneur.