All textual content of MediaWiki.org is released under one of two license options.
Both license options allow anyone to re-use the content in any way they choose.This includes charging money for access to the content, distributing it wherever and however they like, and modifying it in any way they see fit.The main differences between the two license options are:
Image-specific permissions are located on the images' description pages.
The public domain help pages are all contained within the "help" namespace.This means that their page titles will all beginHelp: (for exampleHelp:Contents).They also displayTemplate:PD Help Page on top.
If you are going to contribute to the PD help pages, please ensure thatall contributions come from public domain sources.This means that either you have written it yourself, or you have copied it from another source that isclearly and unambiguously released into the public domain.
Most importantly,do not contribute content released under the CC BY-SA or GFDL or any other "open" license.It may appear that this is acceptable, because there is a certain amount of similarity between the licenses, butPD is not compatible with any other license in the way that the content with any other license can't be relicensed into PD (except that you are the author of the content).However, PD content can always be relicensed into any license.
In particular:
The exception to the above rules is if you are the sole author of content for a page, in which case you may relicense your own material by posting it to the Help: namespace as public domain.Note that this is aone way process - you cannot change your mind once it has been done!