Often irrelevant and, in all cases, does not answer the question.
Used mainly to stop a conversastion about to ensue on a topic the receiving end does not want to talk about. This is, for the most part, used by people who do not think it is morally right to just tell an outright lie.
1: Are you lying to me?
2: How could you think such a thing?
1: Do you like her?
1: How about her?
2: Would you quit with the listing?
1: I'll bet it was you who took the last cookie.
2: I think you're crazy.
The implied denial: Person 2 never said no or yes to the final question or statement in all of the above examples