Email is very useful, but what if you want to talk to someone directly? So chat-rooms were invented. Chat-rooms are found on web pages all over the place, some are public, and some you need a membership for. Once you are in, to use it is simple. There is (usually) as list of the nicknames (or handles, fake names people use on the Internet) somewhere on the page, and when you sign in you give it the one you use. You type something in a text box at the bottom and press either the ‘Enter’ key or the ‘Send’ or ‘Say’ button and your messages is visible to everyone in the chat-room in the text box above, including yourself. IRC chat was designed to go a step further. You need a program for it and it has a few more features (like the ability to ‘whisper’ to only one person in the room).
IM (Instant Messaging) was designed for one-on-one or conferencing, much like telephones. Everyone has a unique nickname or number that you must know in order to contact them with a message, send them a file, or do a real-time chat, depending on what your program supports. You add people to your contact list or buddy list and then if you are online, the program notifies you when they are too. Then you can send them messages, chatwith messages, or do other things.

Some IM programs also let you send them messages when they are offline that they will get when they come online. Something like email, but it works faster. You can also usually invite other people on your list into an existing chat (or messaging) session so that you can have a little chat room with only people you want. There are new features coming out for computers all the time. Many IM programs now let you talk with the people while chatting or even see them! The biggest advantage over telephones? You can talk to anyone in the world for any length of time without paying more than your monthly Internet bill. No long-distance charges!