A channel, also known as a "chatroom" or "room", is run by a channel founder who can give ops, half-ops, or voice to anyone else in his or her channel. A channel is often created around a theme or a group of like-minded people or friends.
AfterX does not permit certain type of channels, and they may be closed with or with out warning. For more information, see rules and the AfterX Charter.
There are many channel modes available for the channel founder and ops to use to help them control the channel and its users. For more information, visit http://www.vulnscan.org/UnrealIrcd/unreal32docs.html#userchannelmodes - a selection of modes extracted from that website is shown below.
Also, ChanServ is a very useful services bot which can help you to keep your channel secure, even when you are not online.