Instant Messaging

Instant messaging: An Internet technology that lets you receive messages, attachments, and other data moments after they're sent.

Instant messaging isn't a toy anymore. While IM started as a way to chat with friends, the technology is becoming an essential tool for business. It offers the convenience of e-mail and the immediacy of a phone call, as well as file transfers and voice messaging. IM is the newest way to keep in touch.

Here's what you need to know:

• Messages arrive in real time because both parties are constantly connected to the network.
  
  
• You can send files and voice messages as well as text messages.
  
  
• A lack of standards means you can communicate only with others who use the same messaging service.
  
  
• Businesses are increasingly adopting the technology.
  
  

The "instant" in instant messaging is possible because the people sending and receiving messages remain constantly connected to their IM service. Recipients get messages as fast as the data can travel across the Internet. E-mail, on the other hand, is less immediate. E-mail technology sends messages to a server that stores the items until they are downloaded by the recipient's e-mail software.

When you log on to an IM service, the software lets a server know you're available to receive messages. To send a message to another online user, you begin by selecting that person's name, usually from a contact list you've built. You then enter your message and click Send. The sent packet contains address information for the recipient, the message, and data identifying you as the sender.

Depending on which service you use, the server either directly relays the message to the recipient or facilitates a direct connection between you and the recipient.

Unfortunately, because there is no standard instant messaging protocol, you can send messages only to people who are logged on to the same service as you are. If you're using AOL Instant Messenger, you can't chat with someone who uses ICQ's messaging software.

Make the Connection

IM services use three means to move messages around: a centralized network, a peer-to-peer connection, or a combination of both.

In a centralized setup, users are connected to each other through a series of servers. These servers link to form a large network. When you send a message, servers find your recipient's PC and route the message through the network until it reaches its destination. IM services such as MSN Messenger use this method.

In the peer-to-peer approach--used by ICQ, for example--a central server keeps track of who is online and what their unique Internet Protocol addresses are. (An IP address identifies a computer so it can send and receive data via the Internet.) After you log on, the server sends you the IP addresses of everyone on your contact list who is currently logged on.

When you want to send a message to another ICQ user, your client sends it directly to the recipient's client, without involving the server. Messages don't go through the entire network. This speeds transfers of large files such as documents and photos because they don't get slowed by network traffic.

AOL's AIM combines the centralized and peer-to-peer methods. When you send a text message, it travels along AOL's centralized network. However, when you transfer files, pictures, or voice messages, the clients establish a peer-to-peer connection.

The best service for you is often the one that most of your friends or colleagues use. If you're not all signed on to the same service, the immediacy of instant messaging doesn't matter.