Instead, users are the product. Advertisers are the customers.
Too bad the original article failed to clearly make this point.
a) people, often students who run their entire social lives on facebook, have 1000+ friends, and spend a long time every day on the site. Often students. Probably don't have much money -- but you might be able to get them hooked with small payments. Also, market it as a gift thing. Your uncle doesn't know what to get you for chrismas, but knows you spend a lot of time on facebook and has no problem spending $20 for a present. Also something to buy for the girl you're flirting with (and yes, it likely is that gendered). Livejournal made this work very well. In this situation it doesn't matter _what_ you offer for the paid account, just that it exists as an option.
b) anybody using it profesionally: event promoters, venue owners, bands, etc. May not deeply like or understand FB, but getting it right is worth serious money to them. Simplification, information management, statistics, maybe tech support.
c) Professionals who know nothing about facebook, but feel they should have a presence there. Sell them a service with lots of hand-holding, maybe integration with tools they already use.
Just here's link for a) http://www.livejournal.com/paidaccounts/
On the other hand, isn't this great for HN users? Facebook is screwing up in some core areas. Up and at'em, I say!