Marketing question: multiplayer [rpg] games

Hello,

I'm not really sure if this post fits this subforum or not but I'll try anyway )

As of lately I have been interested in online text-based multiplayer games - RPGs or possibly simply strategy-type games. I know there have been some great early success stories and obviously the market is now quite different and there is lots of stuff out there. Still I am interested in the opportunities of such a product given today's circumstances.

And, I am aiming for something that is free / or partly free (with additional features available for a subscription fee) and possibly earns a profit from ads.

The development costs are pretty clear to me - however I really do not know how much effort and money would be needed to do a decent SEO - and the subsequent opportunities. In all cases it would be nice to hear from people more familiar with this area than I am, any ideas, suggestions, case studies etc are greatly welcomed and appreciated.