How Facebook Rewards Polarizing Political Ads

As the debate intensifies around Russian ad buys in the US election, a fundamental aspect of Facebook’s platform has gone mostly overlooked. Facebook’s auction-based system rewards ads that draw engagement from users by making them cheaper, serving them to more users for less money. But the mechanics that apply to commercial ads apply to political ones as well.

Facebook has created a powerful system that dynamically, and unpredictably, changes the prices of political ads. The system also encourages polarization by incentivizing ads that users are predisposed to agree with. Unless Facebook makes its internal data public, it’s impossible to say which ads reach which audiences, or how much candidates spend to reach them.