[Mediawiki-l] MediaWiki license question

[John Relent]

Hi all. I have a question regarding the MediaWiki license and the
possibility of developing commercial software on top of MediaWiki; if this
list isn't the correct address, please let me know who I should ask.

I'm considering developing a commercial product on top of MediaWiki. I
understood that MediaWiki is provided with the GPL license, so does this
mean I will have to open up any proprietary code I develop and share it with
the community? Is there a way to obtain MediaWiki under a different license,
and make proprietary developments without having to open them up? Or perhaps
I can develop commercial MediaWiki plugins and not have to open them up?
I'll be much appreciative if you could help me understand which options I
have.

Many thanks,
--JR