Well, obviously a blacklist wouldn't work, so are you suggesting a whitelist? Seems like that would seriously reduce the usefulness. How would you know what foreign-language dissident news sites to include?
What about the ability to spread out a particular request to many exit nodes? This would probably require the establishment of new formats and protocols. How about image formats with the same sort of information as Bittorrent? (Can someone be prosecuted for downloading a fraction of something?) As mentioned in the Rivest article posted recently, there are also "packaging transforms" that allow one to divide information up into n parts, such that all n parts must be provided to retrieve it.
I am surprised that such protocols haven't been devised yet. Yes, this would enable those engaged in child pornography. But those so engaged will just concoct yet another mish-mash of obscurity in any case. (Like using encrypted Windows Remote Desktop connections to virtual servers with encrypted archives on them.)
Just because Bittorrent is used by so-called "pirates," doesn't invalidate it or its use to distribute ISOs of Linux distributions. Likewise, such protocols would patch TOR's weakness at its exit nodes.
