CdM - Person to person? Yes, essentially (other animals could be involved, and it could be argued that other animals do this, but this wouldn't be a useful line to explore.)

ImNotJohn - To do with communication? In a broad sense, yes, but that's not how most people would classify this.
I Say, Porter! - Mime? *shakes head, frowns*

Rosie - Is this an organisation of creative people? No

Kim - Is it a communicative medium? Not entirely sure what you mean by that (and a quick Google doesn't help me). I think the answer is the same as to INJ's previous question.
ImNotJohn - Does it involve a specific subset of people? A specific instance of this would involve a specific subset of people, but in general, no.

Being completely pedantic, this can also be done with/to an inanimate object, so the definition should strictly be ABSTRACT with ANIMAL and possibly VEGETABLE and/or MINERAL connections, but this is another red herring.

Nudge, nudge.

Rosie - Anything to do with sex? *applause* Yes (though the answer (and the thing itself) are quite SFW).