Twitter introduced a feature Monday enabling people to send direct, private messages to any user, as long as that user has opted into the feature.
Previously, users could send private messages (also known as direct messages, or "DM") only to people who followed them on the platform. That meant both users had to follow each other to have a private exchange. Now people can send and respond to direct messages without having to follow anyone.
Users can opt in by updating their privacy settings on the Twitter website, and can stop receiving direct messages from individuals by blocking them.