Will it be "legal" or "illegal"?
Selling in game currency for cash is not "illegal" in that there is no statute in law nor will you go to jail. (I did notice you used "" which means you're aware of that, I was simply stating it for others who may not know)
It may certainly be against the ToS that FD set out for usage of their service in which case FD can do what they want.
The obvious questions to ask:
- for a game to thrive you need to allow people means to contact each other
- one method would be to use global chat channels
- spammers need global chat channels
So you have a choice: allow the community to thrive and in turn enable the gold sellers OR stop the gold sellers' means of communication and kill your community at the same time.
Personally I would:
- Allow chat channels at stations when docked
- Force them to be faction wide only (which makes sense - why would the Feds broadcast to the Alliance ?)
- Create friend channels to talk to all your friends
- For the gold spammer use a report feature that mutes them on your client at the same time (standard stuff)
- Ban the gold spammer with enough reports
As the game costs money this will slow them down, not stop them.
All depends on how popular ED becomes - right now it's a little niche, but I do know that it's a costly business to keep them out.