I am useing whats up for 7 years.I think this is the best social chatting app.Almost every people who have android or windows phone have whats up app.you just need to install the app in your phone then hv to register your phone number and your are ready to chat.It is a very easy process to get connected with someone through the text.You jst need to use a good type of net connection in your phone.all text masseges are free.you can send unlimited pictures, vedios any kind of documents , pdf very esily and in very less time.you can vedio call to someone by this app also.So here your are getting all fecilities by one app only.all are perfect in this app according to me, except vedio calling quality.The quality of vedio calling should be better.Otherwise all are great in this app.I want to rate this famous app 4.8 out of 5 .