The basic difference is that quiet can mean little or no noise, but silent means ZERO noise. If you describe somebody as quiet, it means that person doesn't talk very much. People can also talk quietly (with a very low volume) but itís impossible to talk silently!
Snapchat is a social network based on instant messaging, and its totally mobile based. Its one of the fastest growing apps out there, building its popularity on the idea of self destructing snaps photos or short videos you take to chat with friends before they automatically delete after viewing. Its a massive social app for kids. If youre unfamiliar, check out this step by step tutorial on how to use Snapchat.