This AllThingsD article is interesting-Ecommerce-Pinterest:
Notice how in that system that we have an ad inventory represented by
product pages, the movement of impressions is handled by the act of
pinning the page to pinterest and network effects of the person
network on pinterest. But also notice that there is no costs, other
than enabling pinning of product pages sharing to pinterest, on the
part of the E-commerce entity.
Mobile advertising could be a ad price fee system such as this as it
somewhat matches better the past and future intents of mobile users.
The search engine counter here would be a better way to search
organize product page data coupled to a pinterest competitor and of
course starting a tow tier system of basic freemium services and than
a 2nd tier of premium paid services to replace mobile ad revenues.