My question is actually two questions about GNU GPL and monthly fees:
If I build a server and use GNU GPL as a license, can I run it and charge the users a monthly fee without the need to distribute the source code? My understanding is that since the users buy the service and not the server, I can charge whatever I want without the need to provide the source code. Is this correct?
I know that I can distribute GNU GPL software for a fee, but what about monthly fees? If I provide the newest versions of my software, as well as the source code, only as long as the users pay me, and stop providing the source code and the software when they stop paying, am I violating the GPL?
EDIT: I think I need to clarify that I meant selling original software written by me and my team, not reselling existing software. I guess I'll just RTFL and maybe consult an actual lawyer.