- The public domain help pages are, as the name implies, released into the public domain (PD)
- All other pages are released under the Creative Commons Attribution-Share Alike 3.0 Unported license (CC BY-SA).
Both licenses 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. 两个许可证之间的主要区别是：
- If you alter CC BY-SA content, your changes must also be released under the CC BY-SA.
- Any use of CC BY-SA content must provide credit to the authors.
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 begin Help: (for example 帮助:目录). They have also been given a thick blue border to make them stand out (as you can see if you follow the above link).
If you are going to contribute to the PD help pages, please ensure that all contributions come from public domain sources. This means that either you have written it yourself, or you have copied it from another source that is clearly 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, but PD 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.
You may of course copy it to other places on MediaWiki.org, however.
- Within the site, do not move pages from any other namespaces into the Help: namespace.
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. 请注意，这是一个单向过程 - 一旦完成，你就无法改变主意！