I'm taking the highly unusual (for me) step of blogging twice in the same day, because I found myself extremely passionate when talking about copyright earlier. You can read all about Copyright Awareness Day on How Publishing Really Works
I wanted to give the perspective of someone in the IT industry, because a lot of the dissent I read about copyright is from people in the digital domain. I've yet to see any writers arguing that copyright is a bad thing, but lots of rubbish from other people about how information is "free" and you can't stop the flow of it, so you shouldn't try.
As people point out (endlessly), the software industry has been coping with copyright theft for many years. And it mostly does this by ignoring the problem and hoping that it can sell more games than are stolen. I'm not sure this path of least resistance is really a viable model for publishers, especially since the price point for video games is so high for this very reason. The price of books is not so flexible in this respect, I suspect - witness the pressure to bottom-out the price of e-books, despite the fact that the bulk of the costs of publishing are in the writing, editing and acquisition process.
The mindset in the software world has become even more warped in recent years by the advent of open-source software. Suddenly, everyone can (legally) get everything they need to build their applications for free. If complex software is free, why shouldn't everything be the same way? After all, writing a book can't be any harder than writing a piece of software, right?
Erm, well I've done both and let me tell you the answer is no. The main reason for this is one of collaboration - software can easily be broken into modules and written by a large team of people, but a work of fiction needs a single author (or at a push two) to give the work a unifying voice. Writing well is exceptionally hard work, both functionally and intellectually. And that is what we're talking about here - intellectual property.
Your copyright is important and it is a right. So protect it.