An article about screen can be  very useful, since most new users are unaware of such a utility. In fact, most users never even realise that such a capability could be possible on the command line! But unfortunately, the article does not do a very good job at providing a clear introduction to screen.

1) The text is thoroughly confused about terminology. What the author refers to as "sessions", are actually called "windows" in the screen manpage.

2) The article also confuses a screen window (incorrectly called a session) with the shell running inside it. "exit" has nothing to do with screen. The text says: "To close a screen session where all tasks are finished you can type ''exit''". Exit is not a screen command, its a shell command. It does not close a screen session, it can possibly close the current screen window, because it actually causes the shell to exit.

3) The description of detaching and reattaching sessions is the only part that actually talks about sessions, and not about windows. But it is not consistent in the running example. The article fails to explain how a user can end up with two sessions in the "screen -ls" example. 

 http://www.kuro5hin.org/story/2004/3/9/16838/14935