While a copyright statement in the footer of your website is not strictly required to have copyright protection, it can stop someone claiming in their defence that they didn’t know.
When showing a copyright statement, you should show the Copyright symbol followed by the first date of publication (to the current date, if your site is being updated) and the name of the copyright holder.
James has added support for a [currentyear] shortcode to make it easy to automate this.
To get this copyright statement (where the current year is automatically set to the current year):
© 2007-2009 Tectalic. All rights reserved.
you include in the Footer Text section of your Site Design:
© 2007-[currentyear] Tectalic. All rights reserved.
If you aren’t using an Tectalic website and want to do this in your footer, you can see Lisa Sabin’s article on how to update your WordPress template file.