It's hard to say exactly where the line is that you can't cross without getting killed. Industry experts know more precisely. I suspect the fatal combination is (a) a music focused startup that (b) touches label music and (c) makes money.

I suspect this is exactly right. If you make money, they'll send their lawyers in to extort some of it off you.

And so what's happened is that digital delivery of music has largely been via alternative channels such as P2P. And a new generation of music fans is growing up, liking this, and hating the music industry.