It is also important to consider that a simply copied post with a provided link, but without their own comments, many moderators agree to accept it as a low-quality post. I have reported a few, and if the discussion does not continue, then such posts are simply deleted.
That's understandable and acceptable but from the topic at hand we're looking at the best way to present a discussion that isn't of your original thoughts without been guilty of plagiarized. Irrespective of how the thought is presented from the four options above, I would delete any that doesn't have a continuous discussions as they all can be considered low quality posts. What give them some content is when they're other valuable discussion developing as users pick interest in the topic.