The GNU Free Documentation License (GFDL) causes a number of problems (some of which are stated in http://www.debian.org/vote/2006/vote_001.en.html#amendmenttexta), including:

Because of these problems, the undersigned resolve not to contribute to any of the FSF's documents that are GFDL'd, until such time as their licensing is changed to be compatible with that of the associated software.

  1. Samuel Bronson <naesten@gmail.com>