Some of these are common terms, some not so common. We’ll explain them all.
There are a lot of degrees of fandom! For this, we’ll use the term to mean someone who’s enjoying the show and commenting on the video. Remember, you can still be a fan and criticise what you see (it’ll be a pretty gentle criticism though - at the end of the day they still like it)!
Something that’s referring to itself. For a YouTube commenter, that’s talking about the context of the video – the studio that shot it, the time it was made, the people who are commenting on it. Everything about the video but the content within it.
Adding to the content and extending its value. Examples would be someone providing background about the video, links to related information, etc.
Insulting, criticizing, and threatening other commenters in the thread.
Commenters who say something deliberately trying to get a reaction or start a fight. Toxic.