Im (instant message) instant messaging, as we all know, today's popular QQ, MSN, Skype and so on, all belong to the scope of instant messaging tools. However, these instant messaging tools belong to public instant messaging. That is to say, they are instant messaging tools for the public. They often have a unified central server, all instant messaging users log on to a central server system and establish a start-point connection through the server system. In terms of deployment mode, public instant messaging is generally a centralized mode. Enterprise Instant Messaging (EIM) is technically similar to public instant messaging, but its deployment mode and role are completely different. Generally, an EIM instance is deployed in an Internet Data Center rented by an enterprise based on its own needs. employees in the company log on to the server to establish a start-point connection, conduct Work communication and communication within a specific scope. EIM can also implement the same functions as public instant messaging tools (such as QQ and MSN), such as file sending, audio/video, etc, however, the goal is to improve work efficiency and facilitate office work. The real EIM often provides a collection of office communication media, including instant messaging and collaborative office, and even email and short messages. (Instant Messaging: www.freeeim.com)