Instant messaging lets you communicate with people over the Internet in real time. You can send and receive messages instantly because — unlike using e-mail — you don't have to wait for messages to download from a server. Because of this real-time interaction, instant messages are better for capturing humor and the subtle nuances of communication.
Instant messaging is similar to chat technology. However, chats usually take place within a Web browser plug-in, and instant messengers are stand-alone programs you download and install. People who know each other, especially coworkers and business associates, who want to communicate in real time without any delays, typically use instant messagers.
The greatest advantage that instant messaging has over chat is the ability to create a "buddy list," which is a compilation of your contacts. Buddy lists allow you to create workgroups strictly for business purposes. Alert notices help you track the online status of people on your buddy list so you always know who's available. You can also reach them quickly, usually just by double-clicking on their name.
Instant messaging is usually used for two-way conversations, but some instant messagers also offer a chat option in which your two-person conversation is opened up to a larger group of people. Like chat programs, most instant messagers are available for free. AIM and Yahoo! Messenger are just some of the popular messaging programs available today.

