"Plagiarism is copying from one source. Research is copying from many." Ah, another snappy witticism on Slashdot. More accurately, plagiarism is representing another's specific work or idea as your own. Allow me to demonstrate. Now, if I give you permission to copy, word-for-word, something I wrote and to publish and use it without citing the source, there is no plagiarism. Right? I'm not trying to pick a fight or anything; just clarifying. Anyway, I think that even permitted reproduction of ideas would be considered plagiarism if it was done without actual citation. And, clearly, it's perfectly fine to build on the ideas of others -- as we all know, that's the foundation of academia -- but only as long as you don't pass off that work as your own. If you don't give credit, then it may well constitue plagiarism, even when done with permission. Plus, to steal a great quote, without citation, "Who is the Journal of Quantum Physics going to believe?" Well, I suppose you could always say that it's a "mashup"...