- Bayesian message classification: Add brief definition or description
- Email message formats: The formats and encodings used for text, pictures, and various other objects in an email.
- Email message headers: The header lines in every email message, defined in RFC 5322
- Message digest: An algorithm that produces a fixed-size digest from an input of essentially arbitrary size.
- Hashed message authentication code: A technique for authenticating a message using a hash function and a secret key.
- Internet Message Access Protocol: A client-server messaging protocol in the Internet Protocol Suite, which allows managing messages on the server.
- Messaging (internet): Apps and software for sending text or media via the internet in real-time; also, the act of communicating via such platforms.
- Messaging application protocols: Add brief definition or description
- Off-the-record messaging: A program to encrypt instant messaging (Internet chat) connections.
- Outsourced messaging services: Services to support electronic mail, short message service (i.e., texting), etc., provided by a third party using either a Platform as a Service or Software as a Service model
- Letter (message): Add brief definition or description
- Email: A method of composing, sending, storing, and receiving messages over electronic communication systems.
- Semaphores: Add brief definition or description
- Eduction: A collective term for acquiring information from willing and unwilling people, for purposes including criminal investigation and human-source intelligence, with methods that range from cooperative to coercive