There is a deluge of “creative” free time most college-educated people have. If Uber and Postmates (and countless others) successfully captured the low-end extra work potential of unskilled labor, then there is still a huge potential to capture the high-end extra work potential of skilled labor. Enter in the need for services that let people get “on-demand” services or products from skilled people.
We are seeing it in services like EyeEm and Snapwire, aimed at photographers. And we will be seeing more of it in other skilled professions.