WhatsApp messenger lets people sends instant messages, videos, photos, and short audio messages to either one person or within a group chat. Messages can only be sent to other smartphone users who also have WhatsApp. Once you install the app, it checks your address book to see if anyone else you know is already using WhatsApp, and connects you automatically. You have to be over 16 to use WhatsApp legally. Bullying can take many forms as it is a messaging service and we often hear of abusive group chats. You can block and delete and delete the contact. You can find out more by emailing them at support@whatsapp.com
They say it is good for sending large files?