Posting large amounts copied text is not good communication given the power of the medium. Instead give a short summary of the key substance and a few words on why you think it is important and the link. This gives people the choice to go to the details if they wish or skip it without necessarily having to invest a lot of time.
Some copy/paste jobs and links without any commentary are quite mystifying as they give no clue why the member did it. In some cases I suspect the poster’s understanding of the linked material is not the same as mine but we will never know as we can’t exchange views not expressed.
I also see many new threads created that are not really required. New starters who may not be aware that the topic already exists should be forgiven for starting a new thread on an old subject but there are some regulars who do so often who should know better.
I would not want to see a limit placed on original material, if somebody has gone to the trouble of producing it it is likely to be more valuable than a large copy/paste of text or massed collection of links created with insufficient focus.
Regarding all the above; if the material is important then you can find time do the precis, explain your reason for it, or find the right home for it.
Elsewhere the question was raised about mega-threads becoming unwieldy. If a topic is of enduring interest and attracts many contributions I don’t see the value in arbitrarily dividing it, you are left with the same material in two places and, given the fuzzy edges some topics have, a reader may not know which child thread to look in for what they want.
On the positive side I see a greater number of new posters, or old posters returning after an absence. And we don’t have any cases of 50 cute cat pictures - yet.