Instant messaging or IM is a form of real-time communication between two or more people based on typed text. The text is conveyed via computers connected over a network such as the Internet. Instant messaging typically boosts communication and allows easy collaboration. In contrast to e-mails or phone, the parties know whether the peer is available. Most systems allow the user to set an online status or away message so peers get notified whenever the user is available, busy, or away from the computer.
On the other hand, people are not forced to reply immediately to incoming messages. This way, communication via instant messaging can be less intrusive than communication via phone, which is partly a reason why instant messaging is becoming more and more important in corporate environments.
Also, the fact that instant messages typically get logged in a local message history closes the gap to the persistent nature of e-mails, facilitating quick, safe, and persistent exchange of information such as URLs or document snippets, which can be unwieldy when done using inappropriate media such as phone. Instant messaging allows you to maintain a list of people that you wish to interact with. You can send messages to any of the people in your list, often called a buddy list or contact list, as long as that person is online. Sending a message opens up a small window where you and your friend can type in messages that both of you can see.
History of chat messaging
Later the UNIX/LINUX "talk" messaging systems were widely used by engineers and academics in the 1980s and 1990s to communicate across the internet. MIT's Project Athena created the first instant messaging tool in 1987 with the graphical Zephyr client. PLATO was the first instant messenger combining presence or list of contacts with the ability to send messages. AOL had 6M subscribers using instant messaging when another company named Mirabilis introduced ICQ in November 1996 and was first to introduce this concept freely on the Internet.
