There was once a time when consumers could illegally copy their vhs tapes by wiring up two VCR's. To combat this, a company called Macrovision bought in a system to exploit the TV signal. In fact, it more than exploits the specifications - it breaks them. Therefore Macrovision's signal is an illegal, non-standard signal. Despite the fact the signal is illegal, studios and distributors all signed-up for it.

Macrovision:

Inconvenienced many people legitimately watching paid-for content on TVs.
Reduced the visible picture quality for everyone (even today, esp on 100hz displays).
Prevented the use of projectors.
Oh, and stoped some home users creating illegal copies.

So, everyone was treated like a criminal. Everyone suffered from the signal.

When DVD players were introduced, the signal changed. It is no longer a signal hard-encoded into the picture information, rather it is added "on demand" by a macrovision "chip". That's to say, an otherwise legal picture is fed in and out comes an illegal one. Artificial means of viewing control. One of the things that has disappointed me, is that while DVD-Region control was seen to be consumer-invasive, Macrovision's signal has not been!! I mean, it's not even a legal signal, the fact that it's there means someone has been tampering with it deliberately.

And it hasn't stoped the bigger fish from pirating. I wish Australian law would not require macrovision circuits in DVD Players (dishonour that part of the patent, like the do with RPC). All they do is ruin an otherwise legitimate signal.