Snapchat is rapidly getting popular since last year in my country too.
Major app that people in my country use is called “LINE”.
This is a typical chat app and allowed us to make a phone call for free.
While, snapchat is very popular to those who want to share pictures for a quit short term. So what is appealing to so many people especially young women is that a history of users’ conversation and pictures doesn’t remain unlike other SNS apps. This characteristic of snapchat expresses a real conversation when we have a chat with friends because we never take notes about what we talked about with whom precisely during conversations with friends. Also, snapchat let you know who saved (screenshot) your pictures that you sent. I think this makes users and their friends connected more strongly than other chat apps. I guess that those distinctiveness is the reason why snapchat is popular now.