Are you aware of Facebook's 'other' message folder?

Facebook has a hidden folder marked as 'other' that most users don't even know exist and it could contain important messages they have never seen, it has emerged.

The inbox feature is part of a measure to protect users against spam, according to the social network.

Tech expert David Pogue in a blog post for 'The New York Times', wrote that he had found the secret folder full of Facebook messages that he had never seen.

He said, in order to have access to this 'other' folder, the users need to go the Facebook page. In the left-side panel, they have to click Messages.

There, next to the boldfaced word "Inbox," the user will see a light gray word "Other."

He said the users need to click it to see their hidden stash of messages. He said users may be surprised at how much important stuff has been waiting for them there.

According to Pogue, it turns out that the Other folder is part of Facebook's weird USD 1-a-message programme.

If the user tries to send a message to someone who's not one of his Facebook friends, a dialogue box appears. It offers you two choices: either pay USD 1, or condemn the message to that 'other' folder.

He said Facebook explains that this programme is intended to eliminate spam.

By limiting Inbox-bound traffic to messages from people you actually know (and people who've paid a dollar), Facebook can better ensure that the user never sees junk messages there, said Pogue.