A personal message or private message, often shortened to PM, is like an e-mail sent from one user to another user on an Internet forum, bulletin board system, social networking site (such as Facebook), or chat room (such as Internet Relay Chat).
Personal messages are more anonymous than regular e-mail messages because the e-mail address and IP address of the sender and recipient are not made available, except to administrators and sometimes moderators.
This feature is usually implemented on Internet forums and Internet Relay Chat. Internet forums frequently allow the use of BBCode in personal messages, and in some cases HTML.