Private messaging allows forum members to communicate one-on-one in private, like email, but hosted on the forum.
Send messages to one or multiple users
MyBB's private messenger does more than just the basics: it's an advanced messaging system. Users can send a message to multiple recipients at once, complete with auto-complete username suggestion, as well as select recipients from a list of their buddies. Messages can even be sent to other users blind, without the knowledge of the other participants - just like email.
Search private messages
Since MyBB 1.6, you can quickly find a message using the quick search, or a more specific set of messages using the advanced search options. Both allow you to find exactly the message you're looking for as quickly as possible, and present an easy to follow set of results that include a snippet of each message.
Track and export messages, too
MyBB lets you do more than just send and receive messages. With the tracking system, you can also see exactly when each message you've sent has been read. If a message has yet to be read, you can even "delete" the message, removing it from the recipient's inbox. It's also possible to create custom folders and rename the existing ones, quickly empty folders, and export your messages in CSV, text, and HTML format.