1. A system for integration of client interaction technologies, comprising: a plurality of resource managers, each comprising at least a software service operating in a processor of and stored in a memory of a first network-connected computing device; a plurality of resources, each comprising at least a second network-connected computing device; a monitoring service operating in a processor of and stored in a memory of a third network-connected computing device; and a callback cloud; wherein a first resource manager receives an interaction via a network; wherein each of the plurality of resources periodically electronically reports its status to the monitoring service; wherein the monitoring service determines an expected availability of each of the plurality of resources based at least in part on status reports received by the monitoring service from the respective resources; wherein the first resource manager sends an interactive indicia associated with the interaction, the interactive indicia comprising a user identity and a callback number; wherein the callback cloud receives a first callback request comprising information from the interactive indicia and the expected availability of resources determined by the monitoring service; wherein the callback cloud generates a callback in response to the first callback request; and further wherein the callback cloud comprises: an application server; a media server accessible to the application server; a session management server comprising an interaction manager; and a database; wherein the application server is configured to receive registrations from participating callback providers unaffiliated with the callback cloud, the registrations providing at least a plurality of channels and endpoints from which callbacks may be placed; wherein the application server is configured to receive a callback request from a first user, the callback request comprising at least an indicia of a specific callback provider from whom a callback is requested, an indicia of when a requested callback should be made, and an indicia of allowable media types for a requested callback; further wherein, upon receiving a callback request, the application server directs the callback request to the interaction manager; and wherein the interaction manager directs the session management server to initiate a first callback at a specific time and using a specific channel and resource based at least on the callback request, and the session management server provides signaling to the media server to conduct the first callback using the specific channel and resource specified by the interaction manager.