I fully support the use of P2P to share 'non-infringing content' as you put it.

The web's has reduced the cost of publishing textual information to the point where it is within the grasp of the majority of people in the developed world. That's a fantastic achievement if you think about it - you or I or Auntie Gertrude can now share our views on growing roses or the war in Iraq without undue cost or govenmental control.

Of course, the system has problems. Although the cost of publication on the web is minimal, that cost must still be bourne by the publisher and is a function of the number of readers the published material has. I've heard it called the slashdot effect, when an innocuous small web site or private publication suddenly grows in fame, to the point where the resources of the publisher are exhausted and the site becomes unavailable.

More bandwidth-intensive media excerbate the problem - a new band may publish a few mp3s of their music cheaply using a standard ISP account, but if they become popular they may find themself paying for thousands or tens of thousands of downloads rather than the expected dozen - or of course having to withdraw their free downloads.

P2P technology goes a long way towards solving this problem. The availability of content grows with it's popularity as (hopefully) those downloading it think it worthy of sharing at their own cost. With the cost of publishing spread over a much larger group of people, popular (and bandwidth-intensive) content may once again be published by you or I or Auntie Gertrude. Only now old Gertie can share her photos of her prize winning roses without annying her ISP, and the evidence of atrocities in war-zones can be judged from video source rather than text-summaries in the media.

I imagine in a few years finding magnet link (or whatever they evolve into) on a web-site giving access to a popular audio, video or binary file will be commonplace.

Long way to go yet, but P2P has a valuable role to play. The best we can do to encourage it now is to provide legitimate content.