I'm also a bit of a troll and showoff on occasion.
   I posted a joke that I got but suspected many would not because
   it's "computer nerd humor extreme". So, when I say that "I go by
   the assumption that others will get it" is simply for this very
   fact:

   I haven't the slightest idea who will get it. I can't read
   minds.

   Then, I go by reactions.

   a) If they laugh, they either get it or are being polite. In
   both cases, I need say no more.
   b) If I get a sarcastic response, a 'you're stupid because it
   makes no sense" or a "I want to understand you but I don't get
   it", I explain.

   In short, I assume the intelligence first and see.

   I could go in the other direction and assume unintelligence
   instead.

   But I like giving ppl a chance to surprise me and I'm rarely
   disappointed with the responses, whatever they are.