Long story short, one of the settings in my urban fantasy story is a borderline-ancap society with few to no government-run social safety nets, and I'm trying to get a sense of which of the various fantastical services in this setting people would have to pay for, and what services companies could get away with funding through ad-space. Does anyone know the general rules for what determines if an advertising model is viable or not, so that I can work out whether or not a service with minimal real-world parallels to draw from would be likely to use it?
