Step 1: Don't panic. Step 2: Copyrights.
Today, I submitted my email to register for a free guide to copyrights - in Canada (sorry guys, I live in Canada - for those of you from elsewhere, things could be slightly different).
The BDC site tells me you register for copyright for these 4 reasons:
1.Registering a Copyright will create a public record showing you as the owner.
2.Registered Copyright will become the evidence you need to prove your ownership.
3.You can license your work and charge fees for the use of your work.
4.Protection is the ultimate reason for registering Copyright.
I assume that's all similar in the States and in other countries, but let me know if I'm wrong!
BUT, you don't have to register your copyright. As elucidated on the Canadian Government's website, the owner and creator of a work is automatically protected by law. If you've made something, you already have copyright. Bu if/when you publicize your work, you may want the official certificate the government issues, in order to quickly settle any disputes, should they arise.
But nobody, not the government, not the police - no one is watching to make sure your work isn't plagiarized or infringed upon. You need to watch for that yourself (... unfortunately). At least you'll have a handy certificate if it happens. And the government's copyright registry behind you.
It's also worth noting, you cannot copyright most titles, plot ideas, or characters - a novel gets a copyright, but not until it's written in fixed format. Copyright gives you sole right to reproduce and distribute your work, or authorize others to do so. If someone distributes your work without your permission, that's infringement. People can, however, quote pieces of your work for the purpose of news, research, criticism, or reviews, without violating your copyright - this is called 'fair dealing' in the Copyright Act. In the case of criticism, for news reporting, or reviews, the quoter is supposed to include the copyright owner's name, if known.
One thing to note - trademarks and copyrights are not the same thing. If you want to protect your brand logo (like, say, your personal publishing brand), that's a trademark. Trademarks are any combination of words, sounds, and designs that distinguish your product from others; things like slogans, names of products, distinctive shape or look of the product, or distinctive packaging. These things are protected as trademarks - and you can read more about the specifics here. Like copyrights, you don't have to register it, but if you get into a legal dispute, registering it beforehand will ensure you do not have to prove your ownership (that's up to the challenger).
Oh, I should mention. In Canada it's $50 to register a copyright. Government fees. But... coming soon... IBSNs are free! As many as you want - free for everyone! (That's the next blog)
In summary, it's really up to you. I would air on the side of caution, and register any trademarks and copyrights that are important to you, and that you intend to use for a long time. That way, you play it safe; you have proof of ownership if ever someone tries to copy your stuff without permission.
And in the spirit of learning: today I learned, if you can't get the cheese off the fondue pot, wash it with COLD water. Ha hah!