Should I refrain from posting my poem?

If you are seriously concerned, then you need to get copyright. Not sure where you are but here is a snip on US Copyright Office on Poetry

You won’t lose the right to claim the poem as your own because that’s protected under copyright.

What you will lose are your “first rights.” When a publisher purchases a written work, they want to buy the “first rights,” meaning they are the first to publish it. If it’s already published (and posting something for free online is considered “publishing”), your work will thus lose market value.

I don’t know the law. I do believe that fluther says that anything anyone posts here is theirs. Personally, I think if you don’t want it to get in anyone else’s hands then you shouldn’t let it out of yours.

I have written over 300,000 words here. I don’t consider any of it to be mine. Once I click on “Answer” I feel like the words belong to the world. Anyone can take them and do whatever they want with them. Not that anyone every would, but they could and it wouldn’t bother me.

But then, I don’t think my words are anything to write home about. I just blather along. You clearly think you write good stuff. I wish I could fool myself believe that I wrote anything worthwhile. Must be a nice feeling.

Anyway, my advice is if you are writing good work, the last place you want to put it is fluther. You want to keep it to yourself. Copyright it. Send it off to a publisher. Make some money. It just baffles me that anyone would consider putting some work of art they seriously liked here.

While Fluther reserves the right to use the content submitted by its members for any purpose, copyright is retained by the members themselves. This is a fairly standard arrangement for user-driven sites (though not universal).

Other than that, @HungryGuy has it right: copyright is obtained the moment you fix a work in a tangible medium (of which posting to this site is an instance). There is no need for registration. But the first rights are gone, which is more of a marketing issue than a copyright issue.

The main reason that I was concerned was that If I tried to publish it in my school’s literary journal, and someone looked it up, they would find it here and I would have to prove that it was mine.

It’s a poem.

I seriously doubt that anyone would think you would steal from @PhiNotPi without being him.

@PhiNotPi – Then register it in your country’s copyright office first. I typically do that for my longer works, even if I’m just posting them for free on the internet. In the UK, that’s the Copyright Office. In the USA, that’s the Library of Congress. It’ll be something similar in your country.

@PhiNotPi Again, I’d say either take @HungryGuy‘s advice or make someone from the literary journal create an account and send them a PM saying “See? It’s me. I told you so!” In fact, maybe do both.