Those requirements are one factor Rosati believes is giving rise to a new job category, the "distributed work manager," who understands how to oversee a workforce that never meets and may not work together for a long period of time.

Also rising out of the new trend will be performance management infrastructure, or sets of tools for determining how well the distributed workers are doing their jobs. One of the ways Elance adds value to its own service is with 18 different measures of performance that it applies to the workers whom it connects with employers, Rosati said.

Customers like human-cloud services because they don't have to predict their staffing requirements ahead of time and can get a project up and running quickly without having to find contractors or hire workers, CrowdFlower's Biewald said.

"You can turn on and off people in the same flexible way that cloud computing lets you turn on and off computers," Biewald said.

For the workers, this style of employment means they don't get locked in to roles that may become irrelevant. Programmers, for example, can always be looking out for the next hot skill and then learning it, he said.