Its important to note that while the term messaging can be used to describe e-mail, fax, instant messages and other services where humans read and send the messages, in EMS terminology the word messaging is used to describe asynchronous messages that consists of requests, reports or events that are consumed by enterprise applications and not humans. These messages contain information that is needed to coordinate systems and track progress of the enterprise.
Enterprise messaging systems, which are language and platform-independent solutions, are also called messaging services, or more formally, messaging-oriented middleware (MOM).