Channels are designated as one of the following:
Private Channels - Channels which are seen only by you and the person you are talking to. This will also include grouptalk which may have more than one other person.
Organizational Channels - Channels that are unique to a given organization. This may include racetalk as only a select group of players can see this.
Non-private Channels - These are channels that anyone can see regardless of race or organization.
Non-verbal communication - Socials, emotes, and oemotes.
*Information as of July 27, 2005