The cool thing about facebook’s highly targeted advertising is that it balances the ad market in favor of niche players vs. generalists, which also means they have a long long tail of millions of small buyers vs. a few huge ones who used to dominate traditional media.
Old marketing was carpetbombing, which meant only those with B-52 sized budgets could dominate. It was also deeply entwined with centralized high-volume distribution models, aligning the interests of big manufactures and big retailers.
Today’s marketing is precision bombing. You just need the right explosion in the right place. Likewise, internet distribution enables the economics of small manufacturers and small retailers (shopify/amz third-party).
Which is why big advertisers have done relatively poorly with internet ads. Their prior campaigns worked, not so much because they or the product were good, but because they could silence small competitors. Because retailers could only carry a limited amount of products they would favor the big mfgs who could provide bulk orders. Consumers just went for them because they had no other choice.
Today small player’s can advertise to narrow niches where rates are low. Likewise consumers can access products that better suit their specific needs/wants. What this means is that FB doesn’t really need or depend on big budget advertisers. Mark knows this.