Can you blame him? That article is over a year old. The copyright date on chatterous.com is 2008. I don't understand how that kind of oversight could last for a year on an actively developed product.
And it doesn't matter. Farm Town said for months (and still probably does to this day) "Notify me when myr crops are ready." They misspelled a two letter word. Didn't stop them from getting 30m users. I'm guessing Chatterous's out of date copyright won't hold them back either.
Why? Because the date serves a purpose: so that people can know when your copyright expires and your content falls into the public domain. If you move up the date incorrectly, you are cheating the rest of the world.
As you can imagine, we are not that eager to copy your home page for free 75 years from now, but the law doesn't care.
"Copyright notice was required under the 1976 Copyright Act. This requirement was eliminated when the United States adhered to the Berne Convention, effective March 1, 1989." (First Hit on Google, 2009, p.1)
Having a date and copyright symbol isn't required by the Berne convention, however it can impact the size of damages awarded in a copyright infringement case.