I have two real inboxes: my personal gmail box (firstname.lastname@example.org is Gmail) and my work mailbox which sits somewhere on the servers in my office where people named Alex can find it.
FB as it is designed now can never be a real mailbox for the following reasons:
- No forwarding of messages.
- No filing, tagging or archiving of messages.
- No searching messages or senders.
- No saving, backup or export of messages.
I know some people use FB for real and even business/professional messages. I don't get it, but it's their funeral. I use my FB mailbox as a toy. My Inbox has invitations to events, messages from groups and fan pages, etc. Every now and again a friend writes me on my FB inbox, and I almost always answer them using my gmail account, so I have a gmail record and they will start using real mail to speak to me.
The main advantage of FB is you can send mail to anyone, even people you don't know. The main disadvantage of FB is anyone, even people you don't know, can send mail to you. I have found numerous business contacts through FB, and I have not sent them business email through that methodology. Either I come up with their business email legitimately (pretty easy to do, actually), or I don't write. As far as I am concerned, people are on FB for fun, and the last thing they want is to have people accosting them at the playground to do business. My FB inbox is just a playground. If you want to be serious with me, find me somewhere else.