It's possible to send only the contacts you want to Whatsapp Inc. when synchronizing? In Yappari is possible to choose to only send the ones with international prefix. For me, that function (or similar) to protect privacy of my contacts is a must. Yes, I know, lot of people maybe sent that data already, but I won't contribute.

Now I am using an Android phone (until I repair N900 broken USB port) and I am not using whatsapp because of privacy. Is inconvenient, but I will survive XD.