Internal Messages

Messages are private notes you can send any friend youre connected with on Facebook; theyre viewable only by the person to whom theyre sent and do not go into the news feed or ticker for viewing by your network of friends. Rather, each message goes into the recipients Facebook inbox which functions like a private email address. (Each user is actually assigned a username@facebook.com email address for this private inbox.) By default, messages also get forwarded to the external email address the user has provided to Facebook