A troll is basically one who posts messages intended to insult and provoke. For each person who responds, the troll will consider that person “caught”.
Trolling is considered to have been a complete success if it disrupts beyond repair the normal traffic on a newsgroup or on a messageboard.
~ Source: Fravia’s web searching lore
Trolls come in a couple of variants. There’s the classic spammer troll who posts the same message many times over.
Then there’s the kook, who is a paranoid user who doesn’t seem to have grounding in reality. These days kooks are mostly wokeists spreading consipracy theories. Newcomers to communities can get easily caught be kooks, if the mods do not ban them quickly.
Flamers are community members who don’t contribute anything other than ad hominem attacks.
And lastly, shill is someone who is advocating for a group or cause that is at odds with the community or the topics discussed.
Trolls often work in groups, planning coordinated waves of attacks in wars between online communities. Speaking of crypto communities, anti-crypto groups will naturally make use of starts of bear market or negative press coverage as at those times, crypto communities are weakened. On Reddit forums with good mod team, this will be visible at the very least as downvote brigading: No matter what you post, you will instantly get -10 votes, but there will be no troll comments as those get picked up by moderation.