1983: CBS Airs the Final, Record-Setting Episode of 'M*A*S*H'
If the Dictionary of Teleliteracy were organized by popularity, not by alphabet, the finale of M*A*S*H would [be] at the front of the list: its expanded concluding episode, "Goodbye, Farewell and Amen," which aired on this day in 1983, attracted 77 percent of all TV viewers that night, and earned a Nielsen rating of more than 60. ...
Even more so than the "Who Shot J.R.?" furor over Dallas, the ending of M*A*S*H upped the ante for the perceived value of entertainment as news; an advance copy of the final script was obtained and leaked to The National Enquirer, which treated it like the taloid equivalent of the Pentagon Papers. This left the more legitimate media grappling with a rather sticky question: whether 'tis nobler to ignore the plot details divulged by a usually unreliable source, or to acknowledge them — and so by acknowledging, repeat them. Most newspapers came down on the "this is news, regardless of the source" side, and reprinted the major details, including the central plot surprise that Alan Alda's Hawkeye Pierce would suffer a nervous breakdown. It was the uncredited precedent for the now-common practice of major media outlets trolling national (and, later, TV) tabloids for high-profile news, innuendo, and rumors.
Other, more direct achievements by M*A*S*H included its tasteful and somewhat daring use of a laugh track (when the action took place inside the operating room, there were no laughs to be heard), its status as one of the most successful and artistic TV series ever to be spun off from a movie (its own sequel, TV's After-MASH, was deservedly a flop), and, of course, the M*A*S*H finale's claim as the most-viewed TV episode of all time. ... [As for] its record as the most popular TV show in history? Expect it to last forever.
—Excerpted from Dictionary of Teleliteracy: Television's 500 Biggest Hits, Misses and Events