1. In a computer network having an information source and a device set comprising client devices associated with a user, at least one of the client devices being configured to receive notifications for presentation to the user, a system comprising, at least one processor, and an information agent service configured to receive a notification directed to the user from the information source, the notification comprising data regularized in accordance with a notification schema, the information agent service being configured to access user criteria to determine conditions for communicating the notification to the user, access context information that indicates client devices in the device set that are likely to be online and accessible to the user, select at least one client device from the device set based on the user criteria and the context information, and communicate the notification to the selected at least one client device of the device set based on the conditions; wherein the user criteria comprise user preference information regularized according to a preference schema, and wherein the user criteria further comprise at least one of people and groups data regularized according to a people and groups schema, extended context data regularized according to an extended context schema, or client computing context data regularized according to a client computing context schema.
4. The system of claim 1 wherein the user criteria comprise user presence data regularized according to a presence schema, user location data regularized according to a location schema, and user schedule data regularized according to a schedule schema.