1. A prediction subsystem within an event-collection-and-event-processing system that includes one or more computer systems, each having one or more processors, one or more memories, and one or more mass-storage devices, the prediction subsystem executing on the one or more processors to: receive a stream of action messages, each action message comprising a set of key/value pairs and an action assigned to the action message by an abstraction layer, the stream stored in one or more memories and/or mass-storage devices; and for each action message received in the stream of action messages, store the action for subsequent evaluation of predictions, use the action to generate one or more predictions by input of the action to a predictive model, store the one or more predictions, and output an enhanced action message that includes the one or more predictions.