While most of my collegues will disagree with today's P2P supreme court ruling and I fear the ruling will lead to abusive litigations by record labels, I can't bring myself to disagree with the judges in principle.
Most people used P2P services for illegal file-sharing. It would be silly to suggest that P2P tool vendors and service providers did not know about the ongoing illegal use of their tools and services. They were aware and turned the other way. Some of them even went further by introducing features that interfered with efforts record label companies made to directly prevent file sharing.
This doesn't mean that you are liable for every abuse of some well-intended software you released to the world. But you will be liable if you become aware and did not take reasonable steps to prevent abuse.
In the end, the choice is between destroying the music industry or stiffling a promising sector of the technology industry. Musicians have the power to create wonders for our ears. We the engineers have the power to turn their economic world upside down.
All the talk about how P2P can revolutionize the music industry and fairly reward musicians are just that, talk, because it's not their basket of eggs that is being threatened. If they are so sure, why don't they prove their wishful economic theory themselves instead of sitting on the sideline and yelling at record labels to jump across the chasm of uncertainty?
It is true that DRM solutions out there are terrible but IMHO that's OUR problem. We failed to come up with a more reasonable solution and commerical online music services failed to properly inform their customers on the limitations of the service they are providing. Frankly, I think they intentionally misrepresented the service they sold and profitted unfairly. Otherwise, people wouldn't have bought hundreds of songs through iTunes and they would have gotten upset when they switched machines.
We engineers cannot and should not escape our responsibilities with a few paragraphs of AS IS and IN NO EVENT SHALL [we] BE LIABLE. Power to create is not a license to unleash anything we can imagine into the world. Yes it will be stiffling, sometimes unbearably so. Can we prevail in the end? I think so. We are engineers after all.
BTW, here is the best interpretation of today's ruling I found.