1. At a publishing service computer system, the publishing service computer system including a processor and system memory, the publishing service computer system configured to maintain subscriptions for and send event notifications to consumer computer systems that request notification of specified types of events that are of interest to the consumer computer systems, a method of confirming connectivity and an indication of an active subscription between the publishing computer system and a consumer computer system, the method comprising: the publishing service computer system establishing plurality of subscriptions for a consumer computer system, each of the plurality of subscriptions for notifying the consumer computer system of specified events of interest to the consumer computer system; the publishing service computer system receiving a heartbeat subscription request from the consumer computer system, the heartbeat subscription request requesting establishment of a heartbeat subscription for one or more of the plurality of subscriptions, the heartbeat subscription request indicating that the consumer computer system is interested in being notified of heartbeat events, heartbeat events signaling the consumer computer system that connectivity exists between the publishing service computer system and the consumer computer system; the publishing service computer system establishing a multiple heartbeat subscription for the consumer computer system in response to receiving the heartbeat subscription request from the consumer computer system, the multiple heartbeat subscription specifying a time interval for monitoring the plurality of subscriptions, the multiple heartbeat subscription configured to send a heartbeat event notification to the consumer computer system when the time elapsed since sending the last event notification for any of the plurality of subscriptions at least equals the time interval; sending a first event notification to the consuming computer system, the first event notification corresponding to one of the plurality of subscriptions; upon sending the first event notification, the processor initiating a timer to monitor the time interval to determine when the time interval expires; detecting expiration of the time interval by detecting that the amount of time elapsed since sending the first event notification at least equals the time interval, expiration of the time interval indicative of a heartbeat event; and upon detecting expiration of the time interval, sending a heartbeat event notification to the consumer computer system to confirm that the publishing service computer system has an active subscription for the consumer computer system.