For a small number of Facebook users, a buck is now all it takes to get a message into someone's inbox, even if the recipient isn't a friend.

The experiment seems enabled in part by Facebook's new policies, which remove the capability to block messages from people you aren't friends with. Under this policy, the main Inbox is reserved for messages from friends, or for other messages that Facebook's algorithms deem important. Everything else is routed to an “Other” section.

In the test, users can pay $1 to make sure their messages land in the Inbox, rather than the Other section. Facebook thinks this could be the best way to deliver important messages from non-friends while keeping spam out of the Inbox.

“For example, if you want to send a message to someone you heard speak at an event but are not friends with, or if you want to message someone about a job opportunity, you can use this feature to reach their Inbox,” Facebook wrote in a press release. “For the receiver, this test allows them to hear from people who have an important message to send them.”

Facebook says the test only works between individual users in the U.S., and users will have no more than one message per week routed from their Other folder to the Inbox.

Where's the benefit to Facebook?

The timing of the experiment is certainly odd, given that Facebook is already dealing with blowback from its own privacy policy changes, as well as Instagram's new terms of service (which have now been rescinded in response to user backlash).

Facebook's messaging options (click to enlarge)

While this doesn't sound like it would be a huge revenue source for Facebook, as a way to solve messaging it seems like a kludge. Besides, regular email has worked just fine for the scenarios Facebook describes—no dollar required.

The immediate concern with $1 messages is that it could open the door to spam or other unwanted messages—for instance, harassment from an ex-boyfriend or bullying students—even if that's not Facebook's intent. And now that there's no way to prevent non-friends from sending messages, there's no way for users to opt out of getting paid messages.

The experiment reminds me of Facebook's promoted posts, which let users pay $7 to send their status updates to the top of friends' news feeds. It's a quick-and-dirty solution, rather than one that users will love.