Shared address are address which are shared among some users. They can be from a online wallet, exchange or other gaming platforms, they are not controlled by you and if you win, the system may send it back to the address which you do not control and the amount will not be credited to your exchange or wallet account.
Exactly.
But isn't bitcoinfog a mixer? Why couldn't the user send bitcoin from the mixer to his/her deposit address of an exchange or gambling site?