Though the makers of Snapchat never actually come out and say it, their app is quite obviously intended to erase sexting photos after they have been sent.
The service has one purpose: deleting picture messages a few seconds after you send them to your friends.
On their iTunes Preview they invite you to "show your friends how clever you can be and enjoy the lightness of being!" The accompanying pictures are of bikini clad girls (one with clever app feature placement, that makes them appear nude). So, if you love to send semi-nude pictures to your friends, you now have the ability to delete them before said friend turns on you and decides to post alluring pictures of you all over the internet.
The app is Rated 12+, but if I were to advise a conscientious parent, I would not let my child have this app. The product description lists it as having Infrequent/Mild Sexual Content or Nudity - Infrequent/Mild Alcohol, Tobacco, or Drug Use or References - Infrequent/Mild Mature/Suggestive Themes - Infrequent/Mild Profanity or Crude Humor but they really have no way of knowing what kind of content will actually be shown. And neither would a parent, if they wanted to monitor their kid's cellphone activity.