This is what you will find if you view the source of The Oatmeal. Links to http://pterodactyl.me.

We’re no strangers to such hidden gems ourselves, at Automattic. I won’t say more so you can find them yourself, but if you know where to look, we have our own sprinkled throughout our product line. Not truly advertising per-se, but in the same spirit. Hint: a tad deeper than just HTML source. :)