> I don't remember the what the video tech is called, but newer DVD players and TVs won't display videos that have a specific watermark embedded in it. That DRM hasn't been cracked yet. In theory DRM is impossible, but in reality they only need to stay ahead of the hackers. That's not too difficult.
It's not that easy either. Basically it's an arms race between the two interests. The media interests have money on their side (which can be used to hire engineers to come up with difficult-to-crack schemes), whereas the crackers have on their side the fact that a crack only needs to be found once, and then distributed via the internet, and then the whole scheme is useless. However, the crackers have limited resources and interest, so they only bother if it's really worth their time. So any DRM that hasn't been cracked yet can likely be attributed to it not being worthwhile enough to bother with. Playing DVDs on Linux was seen as worthwhile enough because 1) it wasn't too hard to crack and 2) DVDs were (and still are) by far the dominant method of recording/viewing movies. Yes, streaming video has made a big dent, but not that much; there's still tons of stuff not available on Netflix instant play. And Blu-Rays were supposed to supercede DVDs, but in reality that hasn't happened.
There's plenty of protection schemes that haven't been cracked, but many times that's because no one really cares enough to bother with it. Some proprietary music format that only U2 uses, on one kind of player, will probably be ignored by crackers.