I am far from being knowledgeable about these plagiarism, copyright, and patent issues (although I think that my previous post was basically talking about fair use of those earlier quotes). However, I think that most of the academic works (published studies and such) do contain references somewhere at the end.
Deleted Threads by Admin??
I’ve read a lot of threads where folks complain about the Administrators removing entire threads. While I have no reason to disbelieve the Admins might in fact remove threads, I discovered by accident that the OP’s can also delete their thread(s). (I did so last weekend when I discovered my premise of the thread was false.) When I clicked on my self-deleted thread, the “error” prompt I received was that the Admin removed the thread. So there appears a couple paths whereby a thread can be removed from the forum.