I have to contrast IMDB with CDDB a.k.a. Gracenote. The CDDB guy is popularly held to have screwed over the contributions of thousands of dedicated users when they made their crowd-sourced database proprietary and commercial. Some people I know obsessively catalogued their entire collections, in the spirit of community knowledge, sharing. You have to at least consider that this was Steven Scherf's plan from the beginning, from when it was one of the first, if not the first, popular crowd-sourced sites.
I am that "CDDB guy" you refer to. Note that there were a number of us involved, and I can't tell you how far from our minds any of this was. Think what you like, but perhaps a little reading first:
I know the CDDB guy from an unrelated mailing list to do with binary translation - a hobby of his. When I asked him for business advice, he told me get a good lawyer. Good advice!
http://www.quora.com/How-did-CDDB-become-Gracenote