What Lordshiva1948 said. You can always copyright your content, but that still won't stop people from stealing your content. You should probably contact a lawyer about this kind of stuff if it's really worth the hassle. I, personally, take it as a positive thing if someone sees my work and thinks "Hey, this looks good, I'll use it on my project!". At least it says something about my skills.
Simply put, you shouldn't worry about stuff like that. If the content you are making isn't super professional quality, the possiblities of someone actually stealing it is very, very low.