I think the key to making money on facebook is not by delivering ads but by delivering products and services. For example, TripUp provide a service where you can say where you're travelling and invite your friends to join you or look for people to meet in those areas. That's a goldmine for affiliated sales. Travel services (flights, hotels, hostels, car rental, etc). Local knowledge (internet cafes, guidebooks, taxi services). The list goes on and on.

Ads are an invasion of your viewing space. Smart, affiliated services are a win-win.