it would never cross my engineering mind to develop app like Snapchat. If you pitch it to anyone who played with iOS for a moment, they will laugh at you and say: no fun, I can hold two buttons and take print screen and the purpose of your app - dissapearing photo - is gone. But yet SC managed to raise $8MM. How on Earth is that?? Is it possible that those who took photos have no idea holding power button and clicking menu button with take a print screen??
Don't underestimate the power of defaults. When you send someone a photo through most systems the recipient has to go out of their way to delete it, so they wind up keeping (and re-sharing) things they didn't even intend to. If you want to circumvent Snapchat's retention policy you have to actually care enough at the moment to do so, which is a much bigger barrier than any technical one.
