"Shackles" is possibly the wrong word, but certainly Wikipedia had problems with the GFDL from the beginning, viz.: http://lists.wikimedia.org/pipermail/wikipedia-l/2002-June/002336.html
Never mind! Around the time of that message, Wikipedia relicensed everything without the consent of some contributors anyway, so they could just do that again, except now they're so well-known that the backlash would probably kill them. See:- http://lists.wikimedia.org/pipermail/wikipedia-l/2002-June/002335.html
I thought that anyone contributing to Wikipedia agreed to transfer copyright to the Wikipedia foundation (or atleast give the Wikipedia Foundation exclusive rights), is this not the case?
I'm personally not against the GFDL, but I think its use at Wikipedia was misguided at best. It doesn't do that great outside the narrow "manual" focus.
It doesn't do that great for manuals either. The ability to limit reuse of a manual by another project (through inclusion of an Invariant Section on a Primary topic of that project) is just too obnoxious.
The GFDL does not limit reuse of a manual, you can use it as much as you'd like.