Deliberate or ironic misspelling of "poster," meaning a
twitter user. Noun.
Alternative forms of the word include
poast (n) – a misspelling of "post", referring to tweets.
It can be appended as a suffix behind other words, such as shitpoaster (n) or shitpoasting (v).
Trump was
irritating, sure, but you can't deny he was perhaps this
hellsite's greatest
poaster