Large advertisers with large campaign purses to spend also face frustration in their social media spend but will take advantage of fire-sale pricing that stems from small thinking built into many social media startups from their inception.

The first thoughts a founder should have after they conceive their venture’s basic product or service should be, “How will I get my customers to pay for it and what’s the margin for us on each sale.” It should not be, “How can I get lots of customers to use my product or service for free?”

While it’s not quite a given in the real world, you can usually give stuff away for free and get lots of people to take the offer. When they have to pay any amount for those products or services, they become much more choosy. As the price gets increasingly steep, they become choosier yet. Conversion—the direct marketing term for “converting someone with interest into someone who buys”—is the name of this game—turning triers into buyers. That, and margin on each new customer, so the company doesn’t go broke while it builds a paying customer base.

Facebook seems to have confused its open-to-all, free audience-building offer with its paying-advertising customer offer. While it took in US$ 1.6 billion in the first half of 2011—double the prior year—most of that revenue came from small advertisers, not the big guys (says ComScore). A Wall Street Journal article on November 2, 2011 recounts a Ford Motor Company campaign that spent US$ 95 million advertising its Focus model in traditional media, but less than 5% of the presumably much smaller total online ad budget on Facebook. In part, Ford’s Scott Kelly said that their small Facebook ad buy stopped entirely after the Facebook ads caught fire and went viral. Ford spent the remainder of its online budget on non-Facebook ads to keep the viral fires burning.

Moral: Facebook is penalizing itself for being highly effective with consumers and for its advertisers  by not structuring their offerings to large companies in ways that maximize Facebook’s revenue and profit. All of the consumer traction in the world—and Facebook can fairly claim that distinction for now—won’t pay stockholders dividends if a venture doesn’t build profit into their model from the get-go.

Consider it an object lesson if your startup venture is building traffic and you expect to talk about revenue and profit later.