Apps like Flappy Bird & Snapchat are the darling indie stories that makes everyone think all you have to do is be different, be simple, and you will succeed.

It's true, snapchat was one of the first sexting application for tweens and teens, so it spread virally ... it was popular becuase it wasn't Facebook or Twitter and didn't integrate with them. There were a few other applications out that had the same feature set as SnapChat, even before snapchat, and they went nowhere.

If you cover your bases (simplicity, good user interface, unique features) and get presented with a bit of luck, you might get that viral boost.

However it's EXTREMELY challenging to duplicate the success of something where being in the right place at the right time with the right product was a large factor.