Facebook's promise that it will always be free is looking fairly stretched today, as it has announced a pilot scheme which will force users to pay in order to send private messages to people who are not on their list of friends.
So why is it making this move, and what will it mean for you?
The moveThe website has announced it is testing a new system of charging for private messages to people outside a user's network of contacts. This was previously completely free - regardless of how many messages you sent.
It started a trial system in December where you could pay $1, and when you sent a message to someone outside your network it would also send them a text alert - which would increase the chances of the message being read.
If you chose not to pay the fee, the message would go into a separate inbox in the user's folder.
Now it is adding a charge for sending these people a message at all. The cost is likely to depend on how many followers they have. It is could start at $1, but go up to £10 for popular celebrities and public figures. There will also be a cap on the number of paid-for messages that anyone can receive.
It said: "We are testing a number of price points in the UK and other countries to establish the optimal fee that signals importance. Part of that test involves charging higher amounts for public figures, based on the number of followers they have."
What it meansFacebook is emphasising the plus side of the move: it will prevent spam. It said in a statement: "The system of paying to message non-friends in their inbox is designed to prevent spam while acknowledging that sometimes you might want to hear from people outside your immediate social circle."
What this means for you will depend partly on how you filter your messages. If previously you accepted messages from everyone, then this will certainly cut down on the spam you receive.
However, if previously you blocked everyone apart from friends, this will allow additional people to pay to message you.
The plus side is that it will mean that these people could be messaged by old friends and new contacts - which could prove fruitful. Facebook said it would: "address situations where neither social nor algorithmic signals are sufficient. 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. For the receiver, this test allows them to hear from people who have an important message to send them."
The downside is that those who have specifically said they only want their friends to contact them will suddenly start getting messages from other people.
For those who regularly send messages to those outside their network, this will be a costly change. The move is likely to upset many people who have moved much of their communications into Facebook because it is a free and easy way to send messages. Now it will be just as easy - but could cost up to £10 a time.
What it will eventually cost is still to be seen. Facebook said: "This is still a test and these prices are not set in stone."
But what do you think? Is this fair? Does this renege on the promise that Facebook would always be free? Do you think this is just the first of a raft of new charges? Let us know in the comments.