WhatsApp is a cross-platform instant messaging application where it's possible to make voice calls, send messages, images, videos and PDF documents. It is also possible to make free calls via an internet connection. It is available for Android, iOS, Symbian, Nokia, Windows Phone and BlackBerry. It was founded on February 24, 2009 by Brian Acton and Jan Koum and acquired on February 19, 2014 by Facebook Inc, however it continues to operate as a standalone app.