In the early days of the internet, with the first email systems, bulletin boards and then Usenet, "Netiquette" was a big deal and one reason was because at that time bandwidth was at a premium, still fairly rare, and truly a big deal, most people were using dial-up to access their email and the internet, and having personal computers in one's home was something that was still in its infancy.
"Netiquette" focused on not wasting other people's (limited) online resources, not wasting their time, and indeed, "quality" vs "quantity" of posts on Usenet, as one example, was important. Responding to a post in an alt.rec.photo group? Fine -- just don't quote the other person's post in its entirety and only select out and include the specific portion of it to which you are replying and/or adding your own thoughts. One-line posts were seriously frowned upon. "I agree" posts which didn't include anything else were also even more frowned upon. (There weren't any convenient "like" icons to click on back then.) The idea behind "Netiquette" and all of its various rules was to keep discussions moving along, relevant and not allowing them to be clogged up by one-liners or irrelevant comments. Obviously this was easier said than done in many situations, but transgressors were quickly chided by fellow participants in many groups.
In the early days of web-based discussion forums attached to someone's website, again for a long time "Netiquette" ruled, and people were reminded to stick to a topic, not to go off-topic, don't write one-line responses in a thread, don't quote someone else's thread in its entirety if the need was to only comment on a small section of it, etc., etc. Also, since website owners were paying for the hosting services and such, people who joined for the purpose of spamming a site were a huge problem which had to be zapped out, and people who were deliberately running up their post count in order to achieve some particular privilege were also closely watched. Quality rather than quantity was a watchword for most web-based discussion forums for a very long time.
From the looks of it, "Netiquette" and posting standards in general seem to have eased up significantly over the past several years, if not pretty much disappeared altogether, which is why these days we do see one-line posts, even one-word posts or simply a "smilie" in place of words being the only response to a thread discussion.
Those of us who were around the online world back in the late 1980s and early 1990s still have the tendency to remember those "Netiquette" rules and to try to avoid making repetitious posts which have no intrinsic value or one-liners or gawd forbid, simply using a smilie as an attempt to express something in a thread. Quality rather than quantity..... And then again some of us are just loquacious, so our posts in threads may occasionally veer into the quantity but we still strive for that all-important quality.....