You seem to think everyone is concerned about what is closed or open and will stay away from closed source apps. I would consider myself the most techie person amongst all my friends and family and yet I did not even know whatsapp was closed source (nor do I even care). What matters to people is whether something works well and for chats a big part of it is what their friends are using. If ten of my friends are happily using whatsapp because all of their friends are using whatsapp you think I will be able to convince them to leave whatsapp cause it is closed source? I am having a hard enough time convincing just my wife to get whatsapp on her blackberry. She just is not interested because all her friends are on blackberry chat. Asking her to switch to msn (and all the spam) or anything else will be a lost cause before it even started.