It's a trial program, which Facebook began testing on Thursday. Here is how Facebook described the change:
This test will give a small number of people the option to pay to have a message routed to the Inbox rather than the Other folder of a recipient that they are not connected with.It's not just about making money, though. The new feature is part of some additional changes to your privacy settings which Facebook is making. The idea is to make sure that important messages aren't missed by users.
Several commentators and researchers have noted that imposing a financial cost on the sender may be the most effective way to discourage unwanted messages and facilitate delivery of messages that are relevant and useful.
Some have complained about that happening, but we expect that just like the changes to its Instagram division's ToS, these changes might not win Facebook any love.
The other changes affect Facebook’s messaging privacy settings in such a way that they filter less messages out of your main Inbox and into your "Other" inbox. Previously, users could choose to allow messages from everyone, friends of friends, or friends only. Messages from anyone else were sent to your "Other" inbox, the sub-tab of the Inbox that is often left unchecked.
In the new setup, the above options for friends of friends or everyone is called “Basic Filtering,” which means you’ll mostly see messages from friends and people you may know. If instead you select friends only, which Facebook calls “Strict Filtering,” you’ll mostly see messages from friends.
Why does the word "mostly" sit in both of those statements? It's because Facebook now has the ability to deliver messages to your main Inbox even if they don't fit into your selected categories of senders if the social networking giant believes the messages are "highly relevant."
As an example, if you were in a group thread with three friends and a non-friend, if the non-friend sent a message to you, Facebook might allow that message to reach your main Inbox, because there is a high probability that you would want to see the message.
The use care for the $1 per message feature differs. It might be that someone met you at a conference and wants to make sure you read a message from them, and thus pays the fee. Notably, the change is U.S.-only for now, and each user can only receive a single paid message per week.
In addition -- and obviously a good idea in terms of limiting spam -- the feature only exists for people, not business pages, on Facebook.