Communication programs temporarily connect computers to each other to exchange information. They may use telephone lines or dedicated cables for the connection or connect wirelessly. This allows you, for example, to work at home on the weekend and transfer all you've done to your computer at work before you leave home.
These are not the same as networking programs where computers are actually linked together all the time.
Most communications programs now include many different communication functions in one interface.
A communications program includes one or more of the following actions:
An FTP program manages the moving of files between computers. When you download a file over the Internet, you are using an FTP program. Some programs like word processors and HTML editors include this ability to upload files to web sites so that you do not have to use another program.
The image below is for the program FileZilla which I use. It is a fairly typical FTP program. It shows the folder tree for both the source and destination. You can copy in either direction, in this case by dragging the files or folders from one list and dropping where you want them, just like in Windows Explorer. And, it is free!
In a chat program you join a chat room. You write messages that appear in a window that shows all the messages being sent in this chat room. Everyone who is logged in to this room can read your messages.
The image below is for the program mIRC. Each person listed on the right is "in" the room and can write messages and all the others can read them. Recent chat programs let users format their text with color and even with different fonts. People in chat rooms tend to use a lot of abbreviations and smiley faces.
For more on how to use mIRC: Prometheus Project tutorial on IRC .
An instant messaging program notifies you when your friends are online. Then you can send them messages, which they see immediately. Only the one you send the message to can see it and only you can see the messages that are sent to you, unless you choose to change to a multiple-user mode.
Recent versions of instant messaging include the ability to use video conferencing, to play games together with your friends, and even to make phone calls over the Internet. Examples of instant messaging programs are ICQ, AOL Instant Messenger, Yahoo! Messenger, Google Talk, Facebook, and Windows Live Messenger.
The image below shows what such messages look like in a chat in Facebook. You type your next comment in the text box at the bottom. The Facebook profile picture for the person 'talking' shows at the left.