I'd also presume (and it is a presumption!) that people who are commenting on one platform will likely also to be commenting on another. As in, I would presume they would establish a conversation as the preferred method of internet discourse they digest, as opposed to a one way consumption of data.
This also gives me an opportunity to use one of my favourite Cronenberg quotes: "The monologue is his preferred method of discourse" - Videodrome
This is especially true if the content itself gives authoritative or complete information about something, as Warnock's dilemma (https://en.wikipedia.org/wiki/Warnock%27s_dilemma) described:
""" The problem with no response is that there are five possible interpretations:
* The post is correct, well-written information that needs no follow-up commentary. There's nothing more to say except "Yeah, what he said."
* The post is complete and utter nonsense, and no one wants to waste the energy or bandwidth to even point this out.
* No one read the post, for whatever reason.
* No one understood the post, but won't ask for clarification, for whatever reason.
* No one cares about the post, for whatever reason.
— Bryan C. Warnock """
In this way, I think the voting system became popular, not only because it's usable a mechanism to select interesting information, but also gives an important feedback to encourage the poster, same for the "Like" button. However, they has their own problems.
In truth the polarizing of the Internet is causing a lot of us to be lurkers who may have things to say but do not want to engage in emotional content with strangers, because everything is interpreted so emotionally these days.