Internet Relay chat is the primary means of communication for most hackers.
Every individual appears as the same simple stream of text on a screen.
The only things that anyone on there knows about you, are the things that you tell them. And, of course, you can tell them anything, without them being able to check up on it easily. Let's go back to my analogy of a gang. If an organization wants to find out more information about any given gang, they must do one of two things. Either find someone in the gang that's willing to talk to you, or become a member of the gang yourself.