How can I send email to someone's @facebook.com address without it landing in the "Other Messages" folder?

Question

Facebook filters many messages to the Other Messages folder (http://betabeat.com/2011/12/return-of-laptop-lost-in-taxi-foiled-by-facebooks-obscure-message-folder/).

Does anyone know how they filter incoming mail to @facebook.com email addresses? Can non-friends email users at @facebook? Can apps?

Solution 1

If the user replies to an e-mail in the Other messages folder, that e-mail address is then whitelisted, and subsequent e-mails will end up in the Messages folder.

I read somewhere that you only have to move a message from Other messages to Messages to whitelist the sender of that message, but that doesn't seem to work.

Solution 2

According to this facebook help center post:

You'll see mostly messages from friends and people you may know (ex: friends of friends) in your inbox. Typically, messages from other people will go to your Other folder, and you won't receive a notification about them.

You may sometimes get messages in your inbox from people you're not connected to. Some examples of when these messages may go to your inbox are:

• A friend of a friend includes you in a message along with some of your mutual friends
• A member of a group you're in messages you or includes you in a message
• A friend who isn't on Facebook uses your contact info to send you a message from the Facebook Messenger app.

Additionally, someone you're not connected to on Facebook may pay to ensure their message is routed to your inbox instead of your Other folder.