I doubt if a work draft on a forum counts as being published (though I could see a point in deleting an item from the forum once you have sold the final version). On the other hand, something you truly thought was publishable is something I would keep off the Internet. Yes, you do keep your copyright when you place something in the forum, but you do lose control of how someone else might decide to use it. I tend to share here (with two exceptions) what I write specifically to be shared on this forum with no expectation that it would be publishable. The two exceptions happen to be stories that started life as fan fiction and were, by definition, unpublishable anyway. I am not, however, the most knowledgeable person on this forum on copyright and such so someone else may have a different and more informed view.