It's a very logical and thorough interpretation of what the First Amendment protects in regards to various forms of media. I watched the video of his speech in that conference and it was incredible the way he orated his points logically and broke down the usual wall of arguments that you would see in opposition of those areas of conflict. I've only read a few criticisms of his argument, but they were pretty much just garbage tossed out in an attempt to obfuscate the main issue. Those criticisms did not even address a single point made by Laurence Tribe in his presentation. Take note though, the "garbage criticism" that I speak of was posted by the "usual lawyer" who attempts to attack video games in any way that he can. Tribe's points are quite solid though. The other guy that I spoke of just rants on video game blogs with his ignorance while insulting others, and of course gets flamed since his arguments make no sense and are meant to rile up the masses who don't look deeper into the issue or argument. It's quite funny because he insults Tribe by calling him an "over-educated guy from Harvard".
Anyway, you can head over to Gamepolitics.com if you want to read his actual comments. You will have to sift through other comments though.
In regards to the presentation, as I said, it was a superb interpretation of the First Amendment and its application to various mediums.