In the above lecture, the good Dr Lessig gives one of his masterful performances in which he explores, inter alia, his ideas for a distinction between the amateur - the professional and what he calls the hybrid zone.
Remix - the book
He explores all this and whole bunch more in his new book Remix. I've just picked it up from Unity Books - now going off line to read it.
Strewth - go offline to read a book Paul - that's a bit radical.
Quoting not Stealing
You might also care to look at this other video in which Prof Lessig explores the implications to our cultural integrity consequent to our insistence on penalising our children for using sources to make new culture - or as he has it - "they are quoting not stealing"