This is a load of nonsense, of course. Wikipedia's guidelines for fair use within Wikipedia (which is what the above quotes, unattributed) are not based on any specific legal doctrine about what exactly is fair use.

Suggesting that Lessig violated copyright law because he didn't follow Wikipedia's guidelines is absurd. Here are the criteria that would be tested in court. They are not numeric, they are matters of judgment:

http://www.copyright.gov/fls/fl102.html

Yeah, I'm not at all convinced that it is infringing.

1. It can definitely be argued that it is for an educational use, and I can't think of any valid argument that it is for a commercial purpose.

2. It's a user created music video, so he has a case here.

3. Warner might have a good argument here. Lessig did use about 50s of the song.

4. I really don't see Lessig's presentation as having a useful replacement for the song.

Lessig starts playing a lot of copyrighted material around 9 minutes into the presentation to illustrate remixes.The Muppets song is played at about the 11.00 min mark. The presentation is about 50 minutes long, so I really doubt that his purpose was to violate copyright law or to even play a specific song.

The whole point of his presentation is that copyright law is outdated and illogical.

Whether or not he violates current law from a technical legal standpoint, those samples sited are instances where they shouldn't be illegal.

Those samples were created by other people and he used them as examples of transformative works.