1. A computer-implemented method of managing a chat experience of a user desiring to chat with a selected one of a plurality of businesses or chat hosts, the method utilizing a chat management server running computer processes comprising: receiving a search signal over a first network from a mobile device, under control of the user, to indicate that the user's mobile device is running a dedicated application with a process configured to support a managed chat session and including data characterizing criteria for a business or chat host with which the user seeks to chat; responsive to the search signal, (i) identifying a set of businesses or chat hosts meeting the criteria, (ii) determining, for each member of the set of businesses or chat hosts, whether the member is available to engage in chat, based on member data maintained for each member including physical device status for each seat operator of the member, and (iii)transmitting, to the user's mobile device for display, indicia for each member of the set of businesses or chat hosts, the indicia indicating whether the member is available to engage in chat; receiving over the first network a request message originated by the user on the mobile device to enter a chat channel, the request message identifying a member of the set of businesses or chat hosts that the user has selected for engaging in chat; responsive to the request message, subscribing the user's mobile device to the chat channel for the selected one of the set of businesses or chat hosts, and transmitting to the mobile device, over the first network, a launch-chat command to initiate a chat session over the chat channel; subscribing a user device for the selected business or chat host to the chat channel; and causing messages in the chat session to be displayed through both (i) the dedicated application running on the mobile device of the user and (ii) a web browser running on the user device for the selected business or chat host.