on twitter it's replies being used as comment threads but the expectation is replies, and on CoHost it's comment threads that aren't really replies to the OP themselves, but sharing/'quote tweeting' is used largely for replies in the 'talking in the pub' sort of way (and favs help)
damn but 'talking in the pub' is a REALLY good way to characterize it. i shitpost in the rechosts in exactly the same way as i shout something across the room if i hear something funny and wanna put my two cents in. adhd holler.
whereas a comment is like, i sidle up to someone and go 'hey so i wanted to say this to you....' (i like ur art)(you said a smart thing i agree with)(i really disagree with you a lot but i think we can have a good convo abt. it.)