Listen up, bloggers and everyone else posting creative stuff over the Internet:
It's free, it's easy, and it's your best chance of not having your work getting cut-and-pasted by someone who has nothing better to do.
Do it because your work deserves a name. Do it because you've worked for it, slaved over it, and would rather die than see anybody else take credit for it.
Do it, before those same people justify themselves by blaming you for putting it all over the public domain.
Do it, before their justification becomes the basis of a law that will restrict the same exact freedom that has allowed you to put out your work for all to share.
Do it for your brand. Do it for your work. Do it for your freedom.