First of all, copyright.

I've had a poem stolen.
Imagine my surprise when a friend mailed me a copy of one of my poems with somebody else's name on it. The scoundrel, a student at a middlin' Midwestern college, was in his creative writing classes passing off the work as his own in workshopping sessions. After receiving accolades for the piece (but of course), he adamantly refused to submit it to the college literary mag. The professor, who thought this odd, showed the piece in question to some colleagues, one who'd seen me read the same poem at a venue in Chicago. Then, of course, the question was whether the piece was actually the student's or mine.
He claimed it was his, for a little while anyway. He changed his mind when I contacted him directly and threatened to break his spindly little legs.
Actually, the poem had been heard by someone else BEFORE he claimed to have written it. I said he was a thief, not a genius.

However, I take full responsibility for this debacle. I'm way too free with my words. I can't tell you how many times I've given away a copy of a poem after a reading, or how many times I've offered to email individual poems to people who can't afford books. I done the same when the poems are not yet published in a place where folks can get their hands on them.
I've been approached by teachers, kids, parents--and I've been encouraged by the fact that they were touched by something I've done and can't wait to share it with someone else. Naively, I assumed the poems were going to good homes--not that I'd discover some conniving aspiring wordsmith slapping his name on my efforts, certain that he was operating well out of my radar.
Would this have been different if the poem had copyrighted? I suppose I wouldn't have to threaten to crack a kneecap, but what else could I have done? Legal action? How would that work?
Like Kwame, I don't worry about the things that have already been published (although I suppose some poet could leap out of the blue and claim that every word was his first). But what about those pages that fall out of your notebook, those stanzas passed around so freely at readings and in workshops? What's to keep some bozo in Podunk from commandeering your little darlings?
I've looked at copyrighting, and found it to be a ponderous process with questionable payoff. But now I'm a little scared, and I'm looking again.
I shoulda sued the bastard.