HOW INSTANT MESSAGING WORKS

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Although there are several different instant messaging services available, joining one service won’t necessarily allow you to chat with anyone who uses another instant messaging service. The problem lies in the way instant messaging works.

To use an instant messaging service, you run a special instant messaging-client program on your computer. This client program connects directly to another computer, called a server, run by the instant messaging company.

To find out if someone is online, your client program sends a message to the server, which in turn checks to see if the person you want to reach is connected. If so, the server connects you directly to them. At this point, your computer communicates directly with the other person’s computer; your client doesn’t send your messages to the server again. Once connected to another computer, you can type messages, send video images back and forth, and (of course) send files to each other.

Instant messaging lets you chat with one person at a time. Although you can chat with multiple people, each conversation can only be read by you and the other person. If you want to chat with several people at once, you can create a separate chat room where everyone can type and read messages from everyone else.

Chat rooms are like private clubhouses where you can invite others to join and chat about whatever you choose, be it gardening, sports, or trading MP3 files from your favorite bands. Many people create private chat rooms, which can only be accessed with a password. That way they can create a chat room, swap files and information, and then disband before the authorities even realize that the chat room existed in the first place.

Popular instant messaging services, like MSN Messenger or ICQ, are proprietary, which means that you can’t peek at the source code to see how the instant messaging service works. In case you don’t like the idea of tying yourself to a proprietary instant messaging service, try the open source Jabber (http://www.jabber.org). Like the other instant messaging services, Jabber offers real-time chatting and file sharing, but it uses open standards, so anyone can freely access it without worrying about getting shut out periodically.

TALKING TO MULTIPLE SERVICES AT ONCE

Although instant messaging services work alike, they don’t communicate with each other, so if you have a friend who uses ICQ, but you use MSN Messenger, you won’t be able to chat with each other unless you use the same instant messaging program. If you have friends who use ICQ and other friends who use MSN Messenger, you can either load both instant messaging programs or use one of the following instant messaging client programs that can tap into multiple instant messaging services, as shown in Figure 4-7:

Ayttm http://ayttm.sourceforge.net

Gaim http://gaim.sourceforge.net

Trillian http://www.ceruleanstudios.com

Miranda IM http://www.miranda-im.org

Figure 4-7: A program such as Gaim can connect to several different instant messaging services.

Of course, the instant messaging services (ICQ, Yahoo!, MSN, and AIM) don’t like programs that let you talk to more than one service at once; they want to lock you to theirs. Because instant messaging services, such as ICQ or AIM, are free, the companies make their money by slipping in ads to all of their subscribers. If you use a program like Trillian, you won’t see the ads that ICQ or AIM want you to see.

To discourage people from using unauthorized programs like Gaim and Trillian to access their networks (thus avoiding the advertising), many instant messaging services occasionally shut out unauthorized programs. Although this is usually only until the programmers can figure out how to make their programs work with the service again, it can be inconvenient. That doesn’t mean that you shouldn’t try them—just be prepared for some potential frustration.

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