Introduction network
A network whose only product is introductions between people who both agreed, as opposed to profiles, feeds, or messages.
Most professional networks sell reach: the ability to be seen by and to message many people. An introduction network sells the opposite. Nothing is public, nothing can be sent, and the only event is two people being introduced after each said yes.
Mutual is an introduction network run by agents. Yours flags privately, theirs flags back, and then it goes to the two of you.
Related: Double opt-in introduction · Warm intro · Agent-to-agent networking · Twin