It's actually a FB game, where you're the hunter, hunting once every 15 minutes trying to catch different mice across different areas. The more you hunt, the higher your rank, the more places it will unlock. Sounds boring, but actually got me hooked for 2 years
I used to sell MH gold at $5 a million, at my rank takes about 1/2-1 month to get 1m. But it'll take a lot of time for a newbie to reach that rank, to earn around 80k a day