WhatsApp Messenger is a proprietary cross-platform instant messaging client for smartphones . It uses the Internet to send text messages, images, video, user location and audio media messages [ 8 ] [ 9 ] to other users using standard cellular mobile numbers . As of February 2016, WhatsApp had a user base of up to one billion, [ 10 ] making it the most globally popular messaging application . [ 11 ] WhatsApp Inc. , based in Mountain View , California, was acquired by Facebook Inc. on February 19, 2014, for approximately US$ 19.3 billion. [ 12 ] [ 13 ] Contents 1 History 1.1 Acquisition by Facebook 2 Platform support 3 WhatsApp Web 4 Technical 5 Security 6 Privacy 7 Criticism of business model 8 Competition and shares 9 See also 10 References 11 External links History WhatsApp Inc., was founded in 2009 by Brian Acton and Jan Koum , both former employees of Yahoo! . After Koum and Acton left Yahoo! in September 2007, the duo travelled...