(s)low
what you tell someone that she\he is (usually via an Instant Messenger), as an entertaining way to inform her\him that she\he is slow-witted. It is especially humorous when they just don’t get it.. hence the person’s being ‘(s)low’!!
Kelsey: ..Geez. You're awfully (s)low.

Eric: ...‘(s)low’? Don’t you mean ‘slow’?? If so, I’ll have you know that I run a mile in under five minutes.

Kelsey: I’m sure you do*coughnotcough*.. But no, I mean ‘(s)low’: what »you« are.

Eric: What d’ya mean?

Kelsey: I’m not telling you; that’s for me to know, and for you to one day embarasedly find out.

Eric: But I dunno.. Are you sure it’s not the same as ‘slow’?

Kelsey: The more that you enquire into the meaning of your title--‘(s)low’--the more that it proves your being such.

Eric: How’m I s’pose to know what it means..

Kelsey: You are (s)low, you know..

Eric: Jus‘ shut up, I’m thinking..

Kelsey: About what, *you* and the *word ‘(s)low’*?

Eric: May be, may be not..

Kelsey: Exactly, you are, which be why I call you ‘(s)low one’. Just proves my point.

*Looking too deeply into it, Eric tries the hardest he can to learn the meaning and\or pun of ‘(s)low’, not thinking to simply refer to UrbanDictionary.com.*