… to find out that if you mouse over the XKCD cartoon, you get a metajoke about the cartoon?
We now return you to your regularly scheduled program.
I only knew because someone told me.
Now you have an excuse to read them all again!
I’m pretty sure I found out here on the dope a few years ago - less than 3 more than 1 year.
I’ve already gone through my favorites, the series about Firefly. 
You can’t be the last person because I don’t have the slightest idea of what you are talking about.
No, you’re not. I have XKCD on my favorites list, check it every few days, and only now do I learn of this feature. From you.
XKCD… the best geek comic on the web.
Online comics by someone who could really use an art teacher and an editor: http://xkcd.com/
ETA: OK, so I was second with the link but first with the snark.
Dinosaur Comics has two extra jokes in each cartoon- one on the mouseover and one on the e-mail link.
Weird that you’d bring this up now. I’ve been reading xkcd for years and just learned about the mouseover jokes today, when I happened to pause the mouse over the cartoon for a moment.