In the spring of 2005, a professor handed me a copy of his newest textbook. As I browsed it, I was surprised that the copyright notice had 2006 (the next year) rather than 2005 (the current year).
I assumed it was an advance copy, but I was wrong. The professor informed me it was already for sale and shipping, and that a couple college courses were going to start using it the fall of 2005.
I asked specifically why the copyright notice claimed 2006. He shrugged and said something to the effect of "that's how the publishers always do it."
I know that the Berne Copyright Convention eliminates the requirement for a copyright notice, but are there implications of a future date if there is one?
My understanding is that works fall into the public domain on January 1 after the term of the copyright. Is it therefore normal and appropriate for a publisher to claim the copyright term begins as of the next January 1?
[Off-topic musing: If somebody published a paper in the fall of 2005 that cited something from the post-dated book, should their citation also say 2006?]
(United States)