if a copyrightable work is released under the gfdl, the creator of the work is saying that anyone else may reproduce, distribute, or modify the work, as long as they follow a set of requirements specified in the gfdl. among the requirements of the gfdl are that any new work created from the original work is also licensed under the gfdl—that is, once something is licensed as gfdl, it will always stay licensed as gfdl, and anything which uses it also is licensed as gfdl.