Channels are the available methods that a ticket can be opened and replied to by. Each channel may have its own settings, and some can be activated/deactivated. In the case of social channels, such as Facebook and Twitter, multiple accounts can be created to handle incoming messages.
By default, each installation will have API, Email, Facebook, Twitter and Web channels, as below. In the future it will be possible to develop and publish your own channels.
The API channel is used for tickets and ticket messages that are created using API commands. There are no settings available for this channel.
The email channel is used to handle all incoming emails in to new tickets and replies.
The Facebook channel can handle multiple accounts and will create tickets on new posts on your Facebook page and messages to the page.
The Twitter channel can handle multiple accounts and will create tickets on new mentions and direct messages.
The web channel is used for all tickets opened and replied to via the frontend interface.