Which means it will say it on all of my other blogs too

What about on your sites? Did you remember to update them?

Anyhow, I’ve done some research to find a one-time solution, and it’s as simple as adding some dynamic code into your WordPress theme.

<p>copyright &copy; <?php echo date('Y'); ?> mysite.com</p>

On most themes the copyright information is at the bottom, in the footer. So it’s simply a matter of delving into the code of your footer, and replacing your current copyright date with the dynamic code.

Of course, if you started your blog years ago you can just add the first year followed by a dash, as below.

<p>copyright &copy; 2005-<?php echo date('Y'); ?> mysite.com</p>

When you put date(’Y’) in your code the year from the current date is automatically used. And unless you change your theme you never have to worry about it again.

(note: you can edit your theme by logging into your blog via ftp, or in your blog dashboard look under Appearance/Editor.)