SEEKING ALPHA - Sep 30 - WhatsApp has been discussed as a "group messaging" app, competing with SMS messaging and Skype, Viber and others. But teens increasingly using WhatsApp for the more general and long-term "staying in touch," including sharing status updates and pictures. More and more groups use WhatsApp as a closed-group social network. Both Facebook and Google, have recently put more work into their mobile apps for group messaging. The idea of closed-group social networking was one of the key advantages of Google Plus's "circles," but Google Plus has been slow in spreading among the mass market. The biggest challenge for Facebook, Google and others is to match WhatsApp's ease of use. Many have speculated that Facebook or Google will acquire WhatsApp.