MySpace has started a pilot project to filter out copyrighted videos, using Audible Magic technology. (For those who appreciate irony, AM was created by Sean Fanning, the inventor of Napster.) [Whoops: Error. Fanning's company is Snocap.]

On another front, YouTube is complying with a subpoena to provide the identies of people who uploaded entire episodes of 24 before it was broadcast. (There is a certain circular quality to these stories, since 24 is a Fox program, and Fox is part of Newscorp, as is MySpace. Nothing like a little vertical integration to make a company see the property-rights light.)

And Bolt.com, an online community, has agreed to pay Universal for unauthorized uploads of its music. Furthermore:

Bolt and GoFish also plan to use technology that automatically scans the audio tracks of videos that are uploaded and identifies those that contain songs by Universal and other companies with which it has arrangements. It will pay royalties both on complete copyrighted works, like music videos, and also on so-called mash-ups, in which users add copyrighted music to their own creations.

A really interesting part of these deals is that two of them rest on the ability of the site to use software programs to filter out copyrighted content. It seems to me inevitable that implementation of such technology, if it does indeed work reasonably well, will become a legal requirement for any site that wants to avoid liability for facilitating copyright violations.

The YouTube matter, of course, rests on a somewhat different principle -- that anonymity will not be guaranteed, so you will indeed be held responsible for your behavior.

These developments are salutary -- legal rules should respond to what is technically possible. They always have.