We're all just tryin to make a dollar out of 15 cents.
Make it Rain actually came about from a random email we got. Someone just asked, "Can you make a live wallpaper that rains money?". We said "sure, why not" and took it from there. The popularity was completely unexpected. Sometimes good ideas come from unexpected places.
Technically, Make It Rain has been through a large progression. It started out using Android graphics, which at the time weren't performing too well, so we re-wrote the entire thing using Open GL and resulted in much better performance.