This ID will be your social network Inbox where the main focus will be on Sender and the Message. You will not find usual email components like Subject line, Cc and Bcc as you generally do in most popular email services like Gmail, Rediffmail, Yahoo Mail or Hotmail. Once you have an approved email ID, you can strictly control who can send you messages at your unique facebook.com ID.
Setting up your @facebook.com email ID.
1. This feature is newly introduced in Facebook; hence its limited to a small number of users. To get an early access you will need to request an invite for email messages for your facebook account. Login to your Facebook account and click here to open the request webpage. Click the invite button located at the bottom right.
2. Your invitation needs to be reviewed and approved by FB team for you to enable this feature. Once it's approved goto messages in your Facebook account to activate your facebook email feature.
3. Select a unique username for your Facebook email. Incase you have already set up a user name for your facebook profile, you can use the same here. It will look something like facebook.com/username. Your new facebook email ID will be firstname.lastname@example.org. If you have not created your username for Facebook, you can create it first and then select the username for your new email.
4. Once everything is set up and your new ID is created, you can share your Facebook email ID with your friends and colleagues. All emails sent to this ID will land in the Messages section of your Facebook account. [Reference: Facebook Blog]
Points that you need to remember:
1. Facebook email messages are not what you see in your traditional email system. It does not contain a Title or a Subject line. Just a quick message to any friend.
2. Messages are not categorized according to Subject line (rather there are no subject lines). All messages are classified according to Sender’s name.
4. Its a mode of simple text communication, so don't expect jazzy content you generally exchange in other email clients.