Okay, this is a bit of an odd topic. IRC isn't nearly as popular today as it once was, and is now often used to trade illegal software and, er, naughty content. But it's still one of the best ways to talk to groups of people online.

IRC was created two decades ago as a multi-user chat environment. It was a simple, text-only chat system designed to be very scalable and easy to implement. There are now hundreds of different IRC networks.

How It Works

Like the web, all IRC activity is centered on a server. Each person who wants to chat connects to a server. Each server has many channels, or chat rooms, where people can talk.

When you connect to an IRC server, you must provide a nick, or a unique name. Every person on the server must have a unique nick, so you may be asked to change it before you can connect, or your nick may be modified ("Bob" may become "Bob15").

Let's say you connect to a completely new IRC server, that's never been set up before. So I join a new channel, named "#BrentsRoom". Notice the "#" at the beginning of the name; all channels must begin with that character. Also note that I only use letters. On most servers, channel names can only contain letters and numbers.

If I join a channel that didn't exist, the server automatically creates that channel, and places me in it. I'll see a new, empty chatroom.

Now let's say my friend, Erin, joins the server. She lists all the channels, sees #BrentsRoom, and double-clicks on the name to enter the channel. I'll now see Erin in the channel. Whatever I type in that channel's window will appear to both of us, and ditto for Erin.

(There's an added wrinkle: multiple servers can be connected together into a network, which all share the same channels and users. You can connect to any server on the network to access any channel.)

Security

Whoever creates a channel is given a special privilege: ops. An op (or "operator") has power over the channel; an op can kick anyone out or ban them from the channel for a specified period of time. Ops can also give other people ops. Usually, each channel will have several ops at any given time, a select few with the power and privilege of policing the chan.

It is an op's responsibility to keep the chatters from being annoyed. If someone harrasses others, or posts so much text that it disrupts the conversation (as in, cutting-and-pasting the text of a long document into the conversation), the op may kick the person from the room. If that's not enough, the op can ban a person for any length of time, preventing them from coming in.

In addition, some channels can be protected so that nobody can enter unless they've been sent an invite by someone already in the chatroom. Chatrooms can also be made invisible (so it doesn't show up in the main list of channels) or password protected. These protections can only be added or removed by an op.

Why Use IRC?

Many technical folks still prefer to use IRC to hold group conversations, as it generally has better controls than an IM client, and is often easier to log. If you ever see a website inviting you to "Join us on irc.freenode.net, channel #syllable," you'll know that they prefer IRC.

How To Get It

There are many, many IRC clients out there. The most popular one on Windows is mIRC, while some of the most popular Mac IRC clients are Colloquy and Snak.

Ready to get on IRC? Here's a list of IRC servers.