To answer with a little more in depth, yes it was an mmo, but everything was above board - no gold selling or similar shenanigans.
Sometimes the profit margin was above 50% because I could source the product myself - but then it became an issue of what was my time worth and did I feel like quitting my day job which wasn't in any way stressful? I also had to consider the lifetime of an mmo, who could say how long the game would remain popular?
In hindsight, I should have gone all in and captured the whole market vertically, but then again it wouldn't have remained a side-gig that was on autopilot.
I'll probably write about it all some day, I think some people would find it interesting. I had to put a lot of hats on to make it work: developer, designer, marketer, customer support, accountant, security, ops, affiliate manager, ...