On social networks I found many people who don't answer to some polite questions. In real life it would be considered unacceptable.
I've read an italian resource where it calls this way of behaving denying. Like I deny that you exist by not answering you.
I've read that it's also a manipulatory technique used by narcissists and borderline. Can you help me to make this statement more scientific?
This other question can lead to the answer: Why being ignored is 'painful' for human beings?
It can be useful to check also silent threatment