WhatsApp Messenger is a cross-platform mobile messaging app which allows you to exchange messages without having to pay for SMS. WhatsApp Messenger is available for iPhone, BlackBerry, Android, Windows Phone and Nokia and yes, those phones can all message each other! WhatsApp has gone from a newcomer on the messaging scene to the biggest name in the business, and with that increase in size has come a big jump in the number of people looking to take advantage of the app’s users. If you use WhatsApp, there are a lot of threats out there that you should know about – here are a few of the big ones.