CrowdFlower will price the task based on the amount of time it takes to perform the assignment per unit (the user does the sample task). The startup will break the task into units that can be performed by a single person and price the task accordingly.
How do they break tasks down into individual units? That seems like a tough thing to automate, so they may have a bottleneck there when they try to scale. On the other hand, they could have an upsell opportunity if they can sell people by handling more complex tasks that a "virtual project manager" would break down for them.