If you played a highlight reel of historic inventions, it might go something like this: stone tools, the wheel, writing, the steam engine, some other stuff, and then the smartphone. But progress doesn't only mean gadgets and gizmos that propel humanity forward in bounds — it's also about smaller, yet just as crucial, innovations that make the day to day a bit more convenient. Take an app, for instance, that's whole gist is providing a solution for one specific problem. (Just think back to when you couldn't pay a friend for coffee with a click or instantly ID a song you definitely slow-danced to at your sixth-grade winter formal but have since forgotten.)