If you have not had a chance to watch Lawrence Lessig at the 23rd Chaos Communication Congress, go download it now (torrent, http, ftp).
Lawrence Lessig also goes into some depth about the reasoning behind the non-commercial restriction in creative commons. It comes down to freeriding and lessig does a good job linking the aims of the GPL's copyleft type license with the aims of non-commercial. My good friend Dave, argues the downfall of NC creative commons licenses all the time. Well Dave I got some new ammo in my back pocket now.
Lessig also near the end suggests that the war going on with culture is more important that free software and that free software is just part of something much greater. Lessig is somewhat right, but I don't think this will go down well in a room full of hackers. Lessig finally finishes on the debate for the end of copyright, saying we can have those in debates internally over beer. At the moment they cloud the main issue too much.
The first question is about NC in CC and GPL. The questioner points out that Stallman always talks about moral responsibility not freeriding. Lessig suggests the same questions which made up the GPL for free software need to be raised in the different communities of photography, wiki's etc. So we don't get people from the free software community telling photographers whats best for their community (dave take note).
Its also worth noting there are a lot of good talks which can be downloaded too.