Snapchat is a heavy hitter because of the simplicity it offers. There are several apps that do similar things(send a picture/video with a time limit to friends, after the time limit the message is gone). This app called Wickr offers extra features (sending more than one picture, longer videos, etc.). It separates itself from Snapchat with its focus on end to end encryption and user anonymity. Whether or not these features translate into users is yet to be seen.