 0. The recipients of the call, whether or not they elect to participate, comprise a large, amorphous crowd. The following discussion of crowdsourcing reflects our understanding of three of the most significant types of crowdsourcing: microtasks, "professional" tasks, and "game" tasks. Microtasks facilitated by platforms such as Amazon Mechanical Turk [https://www.mturk.com/mturk/welcome] might be the typical type of crowdsourcing in literature.[http://www.clickadvisor.com/downloads/Howe_The_Rise_of_Crowdsourcing.pdf] Not only is there an open call by an employer to the crowd, the crowd also collaborates on the whole task by each member addressing a small piece of the pre-divided work. Professional tasks, in contrast, might have multiple people working on them, but there is no collaboration among them, and their work usually involve a higher degree of innovation. Game tasks are again a different animal, since they copy many attributes of the other two, but add another layer by aiming to be entertaining as well as purposeful. The following discussion of crowdsourcing reflects our understanding of three of the most significant types of crowdsourcing: microtasks, "professional" tasks, and "game" tasks. Microtasks facilitated by platforms such as Amazon Mechanical Turk [https://www.mturk.com/mturk/welcome] might be the typical type of crowdsourcing in literature.[http://www.clickadvisor.com/downloads/Howe_The_Rise_of_Crowdsourcing.pdf] Not only is there an open call by an employer to the crowd, the crowd also collaborates on the whole task by each member addressing a small piece of the pre-divided work. Professional tasks, in contrast, might have multiple people working on them, but there is no collaboration among them, and their work usually involve a higher degree of innovation. Game tasks are again a different animal, since they copy many attributes of the other two, but add another layer by aiming to be entertaining as well as purposeful. 