Clever copy and paste

Generally, if you select some part of a web page, copy it and paste it somewhere else, you'd expect to see pretty much what you'd selected, maybe with the formatting munged a bit.  Recently, though, I copied something (small enough for fair use) from one of the major sports outlets and was mildly surprised to see that it pasted with a handy "Read more" link including the URL of the article I'd quoted.  You can do that sort of thing in today's wonderful world of AJAX.

I suppose one could see this as an attempt to control copying of copyrighted material, which was muddled somewhere into my initial reaction, but really it seems like a more or less useful thing to do, and completely legitimate for a commercial publication.  For that matter, even in a non-commercial context attribution matters and an automatic backlink could be a nice feature.