What's that law called?
 

Like Godwin's law, there is an Internet law that states something along the lines of:

No matter how outrageous a statement someone will think you were serious unless you include a :D

Can anyone remember it's name?

Yes, it's the Alex law.

Awwwwwww sheeyit. Roger Ebert talked about it, in connection with a piece on Darwin that he wrote. Hang on... at the tip of my tongue....

POE'S LAW.

http://rationalwiki.com/wiki/Poe%27s_Law

Or, at least, it seems to be an extrapolation of Poe's Law, whatever it is (which was apparently stated as :"Without a winking smiley or other blatant display of humor, it is utterly impossible to parody a Creationist in such a way that someone won't mistake for the genuine article.")

I always include a :D after I write something I think is funny.
Unless I forget, then I don't.
Because there's a huge difference (imho) between:

You're an a$s!

and

You're an a$s!
:D

The answer to whether I'm serious or not in what I say is always "Yes." A smiley, therefore, would always be a lie.
:)

WHOAH! Alex used a smiley!!

(quoted in case he tries to change/deny it :evil:)

I wouldn't say always but most of the time.
But you shouldn't use smilies, Alex. It's just not you. It would be like you wearing a big floral hat or something in public...
:D

"Riddikulus!"

Winner winner chicken dinner.

VCM.