William Wilkinson, a designer at MetaLab, makes the point that you shouldn't discard simple ideas just because they're simple or appear stupid. He acted on a simple idea for a Russian Roulette simulator for the iPhone, and made $16k in one month from it.
This is not all that dissimilar to threewords.me. As Gabriel Weinberg reasoned, building a small thing that takes off is a good way to get started as an entrepreneur. And, being an entrepreneur is all about finding opportunities where others don't see them, and exploiting them.