Copywriting is free and automatic. Once you write and publish information on your website it's copyrighted. However, having a date with a copyright on your website does a couple other things that help the authenticity of your website.
Firstly, having a copyright is a gentle reminder that all original text, images and sounds belong to the author and are not to be used without permission.
Secondly, having a copyright on your website with the current year let's people know that you are still active. If you have a website that hasn't created in any new content or posts since 2010 then, it's fine to keep that year on it. But, once something new has been added, update it.
I often find myself looking at a copyright date if I am on a site that looks old and abandoned. If the copyright is old I leave right away. So, if you want to keep make sure your site is seen as active, keep the date current.
And how do you get that little copyright symbol? Not all website platforms offer you a choice of symbols to include it. You can always just write "copyright 2013. All rights reserved." Or if you want the symbol try this cool trick:
Hold the ALT key down and type in the number 0169. When you do that this is what you get: © . It take a second to work. Pretty cool, huh? Now, get to that footer (the footer or bottom of the website is where copyrights are traditionally placed)!