293284
Under the GPL you can sell XOOPS as much as you want (slap it on a CD, put it in a box, sell it at CompUSA). As long as you make the source code available, and you can do NOTHING about someone turning around and selling (or giving away) as many copies of that XOOPS they bought to others.
You can also build modules, from scratch, and put those modules under your own license. However if you incorporate any code from someone else's GPL module, or the core systems, your code must also be released under GPL.
If you modify any of the core or GPL modules, and sell or give away (i.e. distribute) that code then you must make that source code available too, and that code is also covered by the GPL.
If you modify the core and or GPL modules, and do not distribute the code (i.e. for an intranet or system where all clients are purchasing it as a service and it runs on your servers) then you do not need to release the source code.
Of course, this is PHP -- no compilation is possible so technically every time you give someone XOOPS they get the source code anyway... And if you build a module no matter what license you put it under they'll have the source code (so you could sue if they violate the license but it's much harder to hide the code like companies that sell binary-only stuff)
Kevin
