Text entered into the chatterbox form can be seen by anyone currently viewing the website. Only site members can send public messages; to become a site member, Create A New User.
In addition to sending public messages in the chatterbox, you can prefix your message with /me. This results in an italicized 'action' message. For instance, /me yawns would show up in the chatterbox as [yourname] yawns.
If another user is bothering you, you can block all messages from that user. To do this, just type /ignore followed by a space and the user's name. Then you will not see public chatterbox messages that they post. This will also block any private messages to your inbox from that user. To turn off this option, just type /unignore followed by a space and the user's name.
Refresh the page or press the 'talk' button with an empty line to see the most recent messages posted in the chatterbox. Don't worry, empty messages don't get posted.