BUBBLEGUM rock, briefly popular in the late '60s and early '70s, was rock 'n' roll with its essence neutralized. Bubblegum news, as practiced by Bob Shanks and the staff of ABC's "20/20," is information packaged like a Krazy Kat cartoon - anti-news designed not to pierce one's perceptions beyond a mere tickling of eyeballs.

At the other two networks, there were lots of morning-after jokes and sighs of disbelief after ABC premiered its new "magazine" show on Tuesday night. At NBC News one staff member said, "It looked like the amateur hour. I turned it off after the first 20 minutes and one of the guys around here told me, 'You wouldn't believe it, but it got worse.'"

CBS NEWS staffers wrote up a few fanciful in-house news items of their own based on the array of oddities that passed for content on "20/20." One of these had CBS signing Don Hewitt, producer of the esteemed and successful "60 Minutes," to a new lifetime contract "at $8 million a year." There were no plans to change the show's title to "60/60."

"It is the office joke today," a CBS News executive confirmed on Wednesday after "20/20's" debut.

At NBC's "Weekend," which just finished a four-year late-night run and goes to prime time in the fall, there was talk of finding a word to describe "Weekend" other than "magazine" since, it was suggested, ABC may have discredited the term for some time to come.

Even insiders at ABC were chagrined, comparing "20/20" to "Turn-On," another ABC flasco that became a landmark. It was the first show in TV history to be canceled while it was still on the air. The cast and crew who were gathered in Hollywood to celebrate opening night heard the bad news even before the show's delayed West Coast air time; so they had a wake instead of a bar mitzvah.

"20/20" was good for a day of laughter, and then the laughter stopped. And as often happens in television, there came to those who laughed a sudden, sickened, sinking feeling somewhere between the spleen and the soul. And virtually in unison - well, we're using a little docu-drama license here - they had to ask themselves the horrible and inevitable question:

What If It Works?

In fact, "overnight" ratings on "20/20" were not that bad, although one must take into account both the curiosity tune-in value of any show's premiere and the fact that "20/20" was scheduled at the end of ABC's strongest prime-time night of the week - "Happy Days," "Laverne and Shirley," "Three's Company" and "Carter Country."

Perhaps because "20/20" proved consistent in style with the crude and cackly sit-coms that preceded it, there was no indication of huge viewer defection at 10 p.m., when it started, although some drop-off was registered in "20/20's" second half-hour, after Flip Wilson's hanky had become soggy with tears and Geraldo Rivera had completed his marathon expose on the gnoshing of jackrabbits by grey-hounds. What some viewers seemed to find objectionable in the show was not its general air of frenzied tastelessness but rather a short piece that was purchased, not produced, by the "20/20" staff - an Oscar-nominated short called "Jimmy the C" in which an animated peice of clay that looked like President Carter sang "Georgia on My Mind."

This was hardly the frightening thing about "20/20." The frightening thing about "20/20" is that even though it often looked like a Monty Python parody of a TV news show, it may be spearheading a further erosion of dignity for broadcast journalism and sending new shock waves along the already precarious border between TV news and TV entertainment.

The first edition of "20/20" was done very badly, but it's the mentality behind the show that gives one chills. Suppose it had been deft, shiny and sleek, but still bounced merrily from Flip Wilson's boo-boo's to shots of nuclear blast? "David's Frost's Headliners," a bubblegum news entry from NBC (though not an NBC News production), mixes former CIA Chief Richard Helms with John Travolta on the same program, staged before an appaulding audience at NBC's Studio 8-H in Rockefeller Center. Frost's specialty is in proclaiming all celebrities created equal by the media; whether you're Zbig Brzezinski or Charo, you're in the same big "People" magazine hopper to him.

Scheduled for ABC prime time tonight is "1968: A Crack in Time," a semi-documentary about a pivotal year for whom the "co-hosts" are ABC News correspondent Frank Reynolds and actor Cliff Robertson. ABC has promoted the show as if it were another nostalgic romp along memory lane, it has made it look like fun, as perhaps all the information on net-work television will someday be made to look like fun.

As we move into what's sure to be the mega-media decade of the 80s, "20/20" could prove to be the prototype for on-air "magazines" to come. It's true that in a print magazine one may turn a page and go from talk of a new Cold War to a movie review, but print and television are not the same; the juxtapositions on "20/20" were gross and de-sensitizing, the possibility of nuclear annihilation and the illicit sale of jackrabbits made somehow insanely identical in importance (though the rabbits actually got more time).

"60 Minutes" and "Weekened" are both careful to separate hard-core news segments from softer pieces and cushion the borders between them with some sort of establishing context, so that, on "60 Minutes," for example, a charmingly exhibitionist visit from lyricist E.Y. Harburg can comfortably and complementarily follow a tough, depressing report about declining literacy in urban schools.

The really odd thing about "20/20" was that while the packaging was aggressively hip, slick and trendy, much of the content seemed a throwback to the days of television freak-shows like "You Asked for It," "Dunninger" and "People Are Funny." That well-worn footage of a girl kissing a cobra on the head would have looked right at home on "20/20," though of course it would have been edited down to just the tiny split-second of the kiss itself. Then it would be on to, say, Rhodesia, Atlantic City and Suzanne Somers' dressing room.

Whether people who buy "The National Star," "The National Enquires" and "Midnight" on newsstands and at grocery stores really want or need a television equivalent of those publications could be debated. But it certainly seems senseless to squander television's potential for impact, enlightenment and intimate confrontation on a test case like "20/20," and it is embarrassing to see respected and respectable broadcast journalists, some of them honored veterans of the trade, drawn into this kind of tawdry information party. The question arises whether ABC really ought to have a news department at all; the network put the news under Roone Arledge, a sports showman and ex-producer of the Howard Cosell variety show, and his chief operating maxim may be to make the news look less and less like the news.

Bob Shanks, executive producer of "20/20," has behind him a career that includes work on public television's trailblazing "Great American Dream Machine," a program that did manage to mingle the sublime and the ridiculous without confusing the two or asserting they are of equal importance. But Shanks made it clear he thinks public and commercial television are two entirely different beasts in "The Cool Fire," a book he wrote about working in TV.

"Commercial television programming is designed to attract audiences to the advertiser's messages which surround the programming," Shanks wrote. "Inherent creative and esthetic values are important, but always secondary." He was certainly true to his code on Tuesday night. In fact he seemed to have created what from his cynical vantage point might be the perfect show: One that is indistinguishable in tone and tempo from the commercials interrupting it.

If this is to be the future of television programming, if we are going to turn on our sets and have gushing, rushing images just tumble at us in a desperate drive to hold our attention until and beyond the next commercial, and if what we now call "news" on television is going to complete its apparent evolution into Something Else - bite-size morsels of artificially sweetened evolution info, little Pop Rocks for the brain - what on earth is that going to do to our perceptions, which some believe television has irreparably distorated already?

"20/20" managed to take a gross leap backward and a garish leap forward at the same time, and if at first it gave us the giggles, it may on second thought justifiably give us the creeps.