> Wikipedia can note propose original research itself... but in such a
> undefined field... only one more reference would be worth it...
If I may be so bold:
I think the description on "Open Content" is pretty good - I also think that just because it is difficult to find descriptions already written of "free content", it does not mean wikipedia should not attempt to describe it. Put another way, just because we can't point to a common description does not mean that we don't all know (and generally agree on) what we're talking about.
A Google query for "free content" yields 2.5 millions hits - many of these are actually describing "free as in beer" content, not "free as in freedom", and my 2 cents is that "free content" can mean both, just as it can in "free software".
Wikipedia of course, fits both definitions.
Aerik