Tech Cat:"If it is okay to copy an entire article onto a blog with my commentary attached, then what is there to stop me from posting the entire Lord of the Rings novel with a review written by me attached. I just can't buy the argument that it is okay to copy an entire article."
Assuming this is a reply to my post, I'd have to ask you to reread my post or at least quote the portion you disagree with. If you actually read it, rather then just posting "What is so hard about providing a hyperlink to the article you wish to share?" with no supporting arguments, you'd see that I am not saying that one should be able to copy an article. Actually, I'm arguing for the opposite -- as I say above,
"Where the usage starts to be illegitimate is when you start copying and sharing the content with a mass audience, or charging for the content. For example, reposting an article in full, or sharing copyrighted programs or music online."
That seems pretty clear to me. If you are just copying an article in full, that's not acceptable. However, if you are adding significant value -- say you're refuting it's points one by one, it makes sense to quote the parts you are refuting. That's fair use. If you look at the copyright code posted by Jeff, "criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research" are specifically protected as fair use. As XX said, citing quotes and using them in an article is fair use, and standard journalistic practice. Just copying verbatim rather than for use to comment or criticise is not.
As for your assertion that my position fosters "posting the entire Lord of the Rings novel with a review written by me attached", that seems valid on the surface. However, when you look critically, you'll see that there is a big difference in the ratio of newly generated material to original material. In the case of quoting someone in an article, or citing specific points of contention, there is going to be at least a 1:1 ratio, probably much higher of material created by the new author verses the original material. In your hypothetical situation of posting a full book with a (probably 1000-2000 word) review attached, you are posting mainly the original author's work, with just a tidbit of your own in comparison.
To sum up: I believe that distributing copyrighted works is wrong and illegal. However, quoting them (even in full, if that is necessary for the criticism) for the specifically granted types of fair use _is fair use_. That is the definition of fair use. Look at the copyright code. It is fair use. I am not defending those who plagurize -- plagurism is wrong. I am asserting that quoting is not plagurism, but fair use. As is personal copying in whatever amount, for whatever use, as long as the copies are not distributed to others.