You can have your content just fine without anyone taking it from you - just don't publish it. Wanting to both give the content to people and keep it to yourself at the same time is a bit contradictory IMHO. I'm not strictly against people being able to restrict how their content is used, but they definitely should have to explicitly state this. The content itself wants to spread and it will do so if left alone. Unlike your car, remember, which won't magically multiply so that every single person looking on it gets his own version. Anyway, if you want your content to be restricted in some way you should just say so, because what you want is unnatural and exceptional in case of content (and perfectly reasonable, natural and common place in case of your car, where, conveniently, you don't have to do anything if you happen to wan't it to not be stolen).