I would have to concurr with GFDL as being a bad thing. I once was considering creating a phone based service to provide access to Wikipedia and as far as I could tell it wasn't practical.

Sure you can reproduce the content, but you have to include the disclaimers and other superfluous information as required by the GFDL that in many cases doubled the call time.

A few emails to the FSF and they admitted the GFDL didn't even permit audio reproduction and suggested I work with the copyright owner to arrange other terms. (So services for blind people are a no-go).

(A) much better license(s) for content are the creative commons licenses.
http://creativecommons.org/
http://en.wikipedia.org/wiki/Creative_Commons

They actually offer freedom.

P.S.- if you want to create a monopoly over a collection of content, the GFDL is the way to do it. Just add some ridiculously long text that has to accompany any use of the content and it becomes worthless to others.