I found this link on the heels of watching a set of clips from a conference on DarkNets in which an MPAA rep gets dragged over the coals.
Which brings me to one of the comments she made- that some people would argue that physical property and intellectual property are one and the same. That sort of claim is the sort you'd expect to hear from a 19th century snake oil salesman. There's just enough truth in it that some people completely miss how false it really is.
Physical property- like say, your car. I smash the window of your car, hot-wire it, and go speeding off. There is a very solid harm that has been done to you. First off, you're out the financial value of the car- which is sizable. But you're also struck with the inconvenience of being without transportation.
Now, let's say I steal a DVD from you- that's still physical property. Same thing- you're out the value of the DVD, and you can't watch it until you replace the DVD.
Okay, instead of stealing the DVD, I borrow it, rip it to my hard drive, and return it. I've now pirated your DVD. Obviously, you haven't been hurt by this- but the owner of the content on the DVD, the owner of the intellectual property, has been. But by how much?
If you take the premise that I would have otherwise bought the DVD, then I've cost the company the cost of the DVD in that lost sale. I can't speak for everyone, but I generally don't pirate things I would buy- I buy them. The quality is better, and in some cases, it ends up being more facile to manage. Like the Red vs. Blue DVDs versus the online downloads.
You could extend the argument. After all, the implied contract on the DVD doesn't allow unauthorized copies- whether or not I would of bought the DVD, I have a copy without paying. Which raises a very interesting question. Imagine this, if you will. I copied your DVD, and before I watch my copy, I call you up to make sure that you're not watching yours. Let's say we live next door, so it's real easy for us to lend each other DVDs. But I made a copy of yours- so instead of actually carrying the DVD between our houses, I just use my digital copy, but otherwise- it's exactly like lending, which is legal in the realm of copyright.
This is a special-case thought experiment, but the point I'm making is that an illegal copy does not translate to a lost sale. Illegal copies are more like a high-speed lending arrangement.
However, I will concede that there is some harm to the owner of intellectual property, and it derives from basic economics. What illegal copies do is increase the supply. If you have a growing supply and a static demand, prices drop. The financial harm is not in the form of lost sales, directly from pirating, it is the loss of sales from the perceived loss of value of a DVD. The owner of the intellectual property can't sell it at the same high markup that he could before, because the number of copies available has increased so dramatically.
That is the economic threat that piracy poses. And that's what IP law is meant to protect- it's supposed to give the content owner control over the supply.