I am a bit unsure about how a writer's works are protected on this website. I may have missed some rules somewhere, but it seems this site showcases works for the taking. I understand that there could be a code of integrity, unspoken and around, but I was just curious. I myself, have no bad intentions, but just wonder other's opinions on the matter, because I am mostly ignorant myself.
I'm confused about the question. If you're saying that someone could read text here and steal it, well, yes, but that's true of any text anywhere, including text in a printed book. A little typing, and anyone can steal any text. That doesn't mean that the thief can get away with publishing it.
Though more explicitly about posting here and its effects on your chances of that piece being published, this exhaustive thread should give you a lot of information on the subject: https://www.writingforums.org/showthread.php?t=23612 In brief, don't post full works if you intend to publish them anywhere else, don't post large-extracts that are "final draft"-type if you intend to publish them anywhere else, and if you're at all concerned about a piece being stolen don't post it. This is a site to help you improve your writing so it is less the showcase you describe in its intentions, and more a workshop where the work you post should be "first draft"-type examples and representative extracts so that you can learn from those - implementing your learnings on work you intend to submit for publishing.
In addition to what's said, you need to understand copyright. It's fairly straightforward and very worthwhile, especially if you intend to publish. That's not a flippant answer but as it stands your question doesn't make a whole lot of sense.
Gannon has hit the nail on the head. Use forums like this to hone your skill, not that one story that you are sure is going to make you a star in the writing world.
