Not unless it's the same content. Arguably if some of the content is old (old blog posts, tweets, etc.) then you should use a range of years.

As many others have pointed out the whole thing is just a signalling mechanism, and not a strict requirement -- "(c) 2012" says, "Don't steal this stuff, it's copyrighted, and we have actively maintained this page through 2012 so we aren't a company from the stone age."