I was asked a question recently that I wasn’t sure about regarding SEO. How much does a copyright date on a website affect its SEO? It would make sense that an updated copyright date would say ‘this site has updated content’ to the search engines. But does not having a copyright date, or having an outdated copyright date have a negative effect do you think?
I’ve not seen any official post about this from Google or otherwise, but my understanding is that a copyright date has no impact whatsoever on SEO.
Anyone can add a copyright date to a page as part of the text or coded in as a HTML comment, whether that date is accurate or not. But for search engines to accurately measure when a page was first published or has since changed, they rely on comparing different cached versions of it, not on what a webmaster includes as a copyright date. It would be too easily manipulated otherwise.
Search engines also monitor domain registration details and change of ownership details to gain a more accurate knowledge of web site history.