I gave SnapChat a try. (I've used Instagram before.) I can see the allure that it has for teens. And I can see all of the ways that it could be used that wasn't its original intent:
SnapChat was developed by Evan Spiegel and Bobby Murphy, two Stanford University students who were convinced that emoticons were not enough to transmit the emotion that a person might be wishing could be sent with a text message. But they were also nervous that a quick snap of a cellphone camera showing a particular emotion might end up being inappropriate for a social media site where the picture could be posted for all the world to see. So the concept of a time-limited photo sharing application was born. http://fatherhood.about.com/od/fathers-social-media/p/Snapchat.htm
Anyone with kids will want to check this out: http://www.connectsafely.org/wp-content/uploads/snapchat_guide.pdf
Frankly, I think I might prefer SnapChat to some of the ways that I have shared photos on Facebook in the past. I very rarely share anything on Facebook because of privacy reasons (even though I have my settings set to what is supposed to be limiting.) SnapChat appeals to me in the way that I couldn't have anything drifting about and SnapChat seems to lack the personal data mining that Facebook does.