Messaging Open Service Interface Definition

The Messaging Open Service Interface Definition (OSID) is an O.K.I. specification which provides a means of sending, subscribing and receiving messages. OSIDs are programmatic interfaces which comprise a Service Oriented Architecture for designing and building reusable and interoperable software.
Each message has a "Type" and a "Topic" and what messages are received can be filtered by Type and Topic. Messages can be sent to a specific subset of subscribers (Agents) or to all subscribers. This OSID is a general service intended to interface with underlying email, chat, instant messaging, or threaded discussion systems.