The idea of temporary photos made Snapchat extremely popular among teens, it also poses the greatest risk since the photos & videos shared aren't really all that temporary. This false sense of security gives way to many risk to anyone taking the glorified startup for their word. Despite a minimum age requirement of 13 Snapchat themselves have admitted that their age verification is behind. In reality they only meet the bare minimum to be able to collect as much data on as many people they can & that involves the photos & videos you send privately. Every photo & video sent on snapchat gets saved to their servers long after being viewed, until they decide to delete it and that's if they ever decide to. Sending Private photos is only one side of the danger, whoever you send it to can easily screenshot or take a picture using another phone and you'll never be know until you see your photo or video being shared.
When people feel like there's no consequences they forget how to act like, the same goes for kids. Mix this with mind of a kid that is mentally unstable and the dangers are life threatening. Do a quick search for snapchat bullying and you'll get almost endless results of tragic stories and many that were discovered when it was too late.
Even more impossible is leaving it up to the companies to set standards for themselves because this would affect their profits. Profit is all that matters to them not connecting people or creating moments like they claim.