Cool! Though am I the only one wondering how this fits into FB's plans? I suppose they still get all contacts and know how frequently I contact them, which buil

Cool! Though am I the only one wondering how this fits into FB's plans? I suppose they still get all contacts and know how frequently I contact them, which builds very valuable info. (Something MSN Messenger never leveraged, sigh.) I'm still very hesitant about ever trusting anything to FB. Apparently by default there's no notification of changed keys: "WhatsApp users can opt in to a preference which notifies them every time the security code for a contact changes". I guess the question is, does this preference get sent to the server or exposed any other way? If it doesn't then it might be too risky to use this as an attack channel.