I won't be selling the module. Just hosting it on our site (hopefully XOOPS based) and allowing access to authorized users of our site to get into that module. If it was an open source module, it would just be like charging for access to the forum module of a xoop site for registered users.

But in this case, it would be a custom module that had value to the users of the site. There is no way I can opensource the app, and therefore it is looking like it could not be a module of xoops.

Which is fine, the xml-rpc is sorta a way around it, but of course removes a lot of the advantages of using an established cms (at least a gpl'd one), at that point I would likely reinvent the wheel. Again, this is fine, but I just want to know where the lines are and so I can inform my clients and they can make a decission.

If this was a smaller project I might approach the authors and liscence it from them directly, but with all the history and users, it isn't really a possible option.

When THAT is the case, I would say that unless the application's license says that you may not modify the source code it should not be hindered by the GPL codelicense as long as you don't release the module.

like herko said, that's a service, and isn't covered under licensing. you would only need to worry about the GNU/GPL hassle if the people that you were charging, were actually getting a copy of the module for their own use as well (correct me if i'm wrong)

There is no case law to back it up, but your last summary does appear to be the consensus in the open source community.

In fact enough people see it that way that Henri Poole (former the CEO of MandrakeSoft) founded affero.org and created a modified gpl to address network related usuage Affero gpl. I think without case law in some/any country that this thread could go on for ever as it is all interpretation of law, liscence, and copyright.

I'll plan on using XOOPS for now, for this closed source module and other open source modules in the future.