Copyright protection, as I understand it, requires no such registration. Copyright protection only requires that you declare it when you publish your work. So yes, if you write a story and put "Copyright 2005" on it, it is fully copyright protected.

Of course, some copyright protection can be registered, as in the case of corporate logos, slogans, etc..

Now the caveat which goes to your question. Neither patent nor copyright protection is permanent. I, for example, own the registered copyright for a corporate logo. If I want to maintain that protection, I have to pay a fee every several years. Since I shut down the company, it's safe to say that I won't be renewing the registration next time. So at that time, anyone who wants to will be able to start using my logo. In the meantime I have no intention of spending money defending a logo that I no longer have a use for, so in a practical way my logo is already unprotected.