Sometimes there's the "don't argue with a fool, a bystander may not recognize who's who". Well, each situation is different.
You also have the case of a twitter who twits a twittee, continues to make references about the twittee, and then out-of-the-blue, starts conversing with the twittee again (thus sublimating the twittee back into non-twittee status).
Geez, that was a mouthful.... <g>