Described is a schema-based notification platform that provides
regularized notification handling including user control and
normalization of the operation of policies across different information
types and contexts. Information-service schemas and services are combined
to build a content-sensitive and context-sensitive information service to
communicate information to recipient devices of users that subscribe to
those services. An information agent service collects the information,
and based on various criteria, determines if, when, and how to send and
render the information, and to which subscribing client device or
devices. The set of schemas include a notification schema that represents
the subscription of a service to an information source and details about
that information, and a device schema that represents information about
user devices. The information agent service accesses criteria including
user preferences and user contextual information, including presence
information, location information, and schedule information along with
people and groups data and extended-context data. Preferences about
subscriptions and information handling policies may be stored and used at
notification sources or in more central preference encodings. Access to
multiple preferences is maintained, and a user interface is provided that
allows users to inspect and control multiple subscriptions in one
conceptual place.