Anonymous wrote:
you can sell a service(installation, customization, etc) not the cms itself .. so yes.
That is absolutely false.
XOOPS is GPL software. The GPL does not stipulate any pricing for software - it stipulates rights of use for the software. Specifically, it stipulates that the person receiving the software must also be given source code (though it includes the note that the vendor can charge reasonable media costs to do so) and they are free to redistribute it as they see fit (as long as they, too, abide by the license).
This is a fine line, but one worth drawing. I worked for a company that sold a modified gcc (GPL'd compiler). I think we sold 4 copies to clients that really wanted them. Of course they could have given it away after that (with source!), but that's not how it worked out.