Did you do it in another language?
Seriously, if you're talking about having posted something by accident and want to "make it go away," all you have to do is click on the button that says 'edit.' (But you have to be quick like a bunny, do it before anyone posts an answer.) There's an opetion on the 'edit' page for 'delete this post.' And -- POOF -- it's all gone.
But maybe you meant something else.