She controls all the gambling, alcohol and sex trade within her city but will not branch off into narcotics as she feels it will cause more problems that the family simply does not need. Not everyone agrees with her decision on this matter, but they were quickly silenced and put into their place by the Godmother, most likely squeezed into trash bags and then dumped in the trash somewhere after Selene showed them the error of their ways, permanently. Those who ask the Godmother for a favor are expected to give a favor in return if she ever asks for it, those that wrong the family in any way or whom get into debt with the family are brought before Selene, where that is last the world will ever see of them, soon just another trash bag filled of unrecognizable remains dicarded in a dumpster somewhere.
Will you be made an offer you can't refuse? Perhaps you will start to work for the Corleone family or maybe you will become one of those permanently disposed of by Selene herself. Either way, it should be fun for the Godmother at least.