From a biography of Ray Johnson at http://www.rayjohnsonestate.com/
As his contemporaries became famous, Johnson receded from view, cultivating his role as outsider while maintaining his profile by communicating via mail art and the telephone. He parodied celebrity in performances, fake openings, photocopy-machine art, lists of famous names next to obscure names, and rubber-stamped signatures such as "Collage by Joseph Cornell," or "Collage by Sherrie Levine." Johnson, referring to himself as a "mysterious and secret organization," achieved legendary status as the conscience of artists. This underground reputation prospered well into the 1980's, despite his general absence from the scene, and the gallery-going public's sketchy notions of his output.