Always give credit where credit is due
if you didn't write it, don't say it's by you
just copy the credit along with the work
or else you'll come off as an arrogant jerk
Always give credit where credit belongs
we know that you didn't write Beethoven's songs
pretending you did makes you look like a fool
unless you're Beethoven - in that case, it's cool
A transparent system makes cheating unwise
the simplest web search exposes your lies
no one wants their reputation besmirched
which happens to liars when they are web-searched
Proper citation will make you a star
it shows that you know that we know who you are
Plagiarization will only harm you
so always give credit where credit is due!
From Ms. Paley's essay:
Attribution is a way to help your neighbor. You share not only the work, but information about the work that helps them pursue their own research and maybe find more works to enjoy. How much one is expected to help their neighbor is determined by (often unspoken) community standards. People who don't help their neighbors tend to be disliked. And those who go out of their way to deceive and defraud their neighbors - i.e. plagiarists - are hated and shunned. Plagiarism doesn't affect works - works don't have feelings, and what is done to one copy has no effect on other copies. Plagiarism affects communities, and it is consideration for such that determines where attribution is appropriate.
At least that's the best I can come up with right now. Attribution is actually a very complicated concept; if you have more ideas about it, please share.
Ms. Paley's Website, "Question Copyright."