1. A computer-implemented method for facilitating performance of tasks from task requesters by mobile human task performers, the method comprising: receiving information about multiple mobile human task performers who are available to perform tasks in multiple geographic locations, the received information for each of the mobile human task performers indicating a current geographic location of the mobile human task performer and one or more mobile devices of the mobile human task performer that are available for use in performing tasks; receiving information from multiple task requesters about multiple tasks that are available to be performed, each of the tasks having criteria for performance of the task that includes a geographic location of a mobile human task performer who performs the task and that includes one or more capabilities of a mobile device of the mobile human task performer who performs the task; and for each of at least some of the multiple tasks, automatically identifying a mobile human task performer who is capable of performing the task in accordance with the criteria for the task, the automatic identifying being performed by a configured computing system and including determining that the current geographic location of the mobile human task performer is within a predetermined distance from the geographic location for the task and including determining that the one or more mobile devices of the mobile human task performer have the one or more capabilities for the task; sending information about the task to the identified mobile human task performer via at least one of the mobile devices of the identified mobile human task performer, the sending being performed by the configured computing system; and after the sending of the information, receiving information from at least one of the mobile devices of the identified mobile human task performer that the task has been performed by the identified mobile human task performer.