A long cut and paste included in a post by someone who is trying to develop some argument is one thing. It's better to give a link and a summary indicating why the piece linked to might be worth visiting, but it's no different in principle from using a quote to add muscle or colour to what you are saying. In a way it is rather like singing a song someone else wrote, as a way of making a statement.

And there are other occasions when there is some reason why an article, that the identified poster thinks is highly relevant, may not be accessible through a link - maybe it's on a site where you have to pay to get in, or something like that

Something quite differentis when an article gets shoehorned in here, with no indication whatsoever that it is anything other than a post by a Mudcat member or GUEST. The problem with that is the way that it undermines the give and take of the Mudcat, because you can't argue back and forth with someone who isn't there and never has been.

I don't think banning is the answer. But that kiond of behavuiourn should be recognised it as bad manners.