Personal messages (or pms for short) are a lot like posts, but instead of being posted in a topic they are sent to one or more members. Typically, personal messages are private correspondence, and they are only viewable by the sender and intended recipients - administrators cannot view other's messages except through the database.

Personal messages cannot be sent by guests or to guests. However, if the sender is deleted sometime after they send the message, they will appear as a guest.

By default, 4,294,967,296 personal messages may be sent on your forum. Since this is a much larger number than the members you can have, it's unlikely you will ever reach it.