Facebook is changing the way messages appear to make communication easier. Now, when someone sends you a message who isn't at least a friend of yours or has your phone number, it will appear as a "message request," which you can choose to accept or ignore.
With the old system, these messages appeared in a folder next to your Inbox called “Other.” It might not look familiar to you because these types of folders (Other, Unread, Archived, Junk) don’t appear on your desktop. Generally, you would have to add someone as a friend first to see their messages in your Inbox or on mobile devices.
Of course, no one wants spam messages, so Facebook says it will continue to filter messages. “Message requests” are starting to gradually appear to all Facebook users today.

