I'd be curious to know how many people would need to use such a service for the ad maker to make the same amount of money. Basically, what I'm wondering is if i

I'd be curious to know how many people would need to use such a service for the ad maker to make the same amount of money. Basically, what I'm wondering is if it would be similar to Wikipedia where a very few percentage of people need to contribute for the system to work out?