As of August 17th, 2005 the LQ Wiki allows you to use either the CC by-sa license or the GFDL. All articles in the main namespace are licensed under the CC by-sa license (which is how is has been from the beginning). All GFDL content must go in the GFDL namespace. It is important to understand the license of the content you are submitting. You should verify that you are not mixing content from two incompatible licenses. If you are submitting original content we strongly recommend you use the main namespace.
This was done after careful consideration. The current objective of the LQ Wiki is to create the "largest general Linux knowledgebase on the web". To meet this goal, I think we need to embrace the fact that the Open Source community consists of documentation that is under multiple licenses (for better or for worse). As always, your feedback is appreciated.