That’s another common misperception, that Facebook sells data. They don’t. They sell targeted advertising that uses that data. The advertiser API specifies desc

That’s another common misperception, that Facebook sells data. They don’t. They sell targeted advertising that uses that data. The advertiser API specifies descriptors for who should see the ads. There’s no facility for accessing private data. Selling the data itself would be giving away a huge component of what differentiates their product from other advertising platforms. It would be like Coca Cola selling the recipe for Coca Cola.