> Facebook cares a great deal about its users--advertisers.

> You and I aren't Facebook's users

A user is someone who uses a product, by any reasonable definition.

Advertisers are certainly (commercial) customers, but the average person IS a user of Facebook.

> we are the ore Facebook has been mining

This I do agree with, my own metaphor has been harvesting rather than mining (like in the Matrix or in Jupiter Ascending). But being something mined/harvested does not preclude also being a user.