It turns out you don’t always get a notification to alert when messages arrive from people with whom you are not friends with on Facebook, meaning they are nearly always missed. In other words, it basically works as a spam inbox. If Facebook decides something is probably spam, some messages are diverted to a special folder ‘filtered requests’ in the ‘Message Requests’ inbox, where it can lay around unread. Facebook only notifies you if it senses you might know the sender, otherwise everything else is assumed to be spam. Previously, it was revealed a secret Facebook folder marked as ‘other’ could contain important messages users have never seen. To view all these filtered messages, follow the steps below: All of the messages Facebook deemed as spam will automatically appear and in chronological order. Since, you won’t be getting notifications about the filtered messages, it may still be worthwhile to check every now and then to ensure that you do not miss out any important message.