Free Software
Devin makes an interesting and valid point, but I disagree with his assertion here:
Without the collective network of millions, Facebook would not exist. We are the customers because we’re paying with a different (and arguably, more sparse) currency: attention.
We are the product. Advertisers are the customer. This may seem like a semantic distinction — at least in context — but there is a fundamental difference in how customers and products are treated, even if both groups are made up of human beings.