Adding copyright to your website reminds users that the content on your site was created by you (it was, wasn’t it?!?) and that you own the rights to it.
Because websites are generally created over time, the copyright information contains two years – the year that the information was first published to the internet and the year when changes were last made. Many websites simply update the last date to the current year in January, but it really shouldn’t change until you put new content on your site.
Besides reminding people about who owns the content on your site, your copyright information helps users to know that you are adding new material to your website. A website with the current year’s date in the copyright seems much fresher than one that is dated even one year prior. Internet users expect web content to be refreshed and updated regularly.