Remember how I used to tell you that the best way to vent your frustration at the tawdry content of commercial television programming was to write a letter to network executives expressing your outrage?

Well, that was then. This is now. And today, the way to impact commercial TV is to get the advertisers to talk to the networks. With their checkbooks. It's amazing how clearly the message is sent when advertiser dollars do the talking.

For example, ABC was all set to air an entertainment special last Saturday night called "Crimes of Passion 2," in which real-life brutality - two stabbings and an incineration - was to be re-enacted for the voyeuristic pleasure of blood-lusting audiences. But even though the first "Crimes of Passion" installment last October was a respectable (and I use that term loosely) ratings performer, advertisers, sensitive to the current climate of viewer dissatisfaction with TV's trends toward tabloidism, were reluctant to sign on with the special.

No, I take that back. They treated this thing like Manute Bol treated Jazz jump shots. Total rejection.

When no advertising - that's right, none - had been sold on the program by late Friday afternoon, ABC pulled the show and replaced it with two failed comedy pilots left over from the 1988 tryout season. The sitcoms bombed, of course. But at least there were a few ads.

"It happened because there is a sensitivity on the part of advertisers to programs of this nature," ABC vice president Ted Harbert said of "Crimes" ' failure. "That's clear, that's obvious and that's growing."

Which, as I see it, is both good news and bad. I'm pleased to see viewers find a legitimate forum for their concerns. But I do worry about the prospect of censorship. Don't get me wrong - I'm all for artistic self-restraint, and would be thrilled if we could eliminate the crude language and graphic violence and sexuality we see on TV. But when we start giving advertisers control over program content, how are we going to stop them when they begin regulating the expression of unpopular ideas?

Still, you need to know that there's a new option available to hear your complaints about declining TV standards: advertisers. (And who would've thought that Madison Avenue would be our chief ally in the battle against teletronic sleaze?)

-ON TV TONIGHT: VCR ALERT!!! KUED will present a special late-night showing of one of the all-time great film comedies, the 1938 Oscar-winning version of Kaufman and Hart's marvelous play, You Can't Take It With You (10:35 p.m., Ch. 7). Directed by Frank Capra, this light-hearted romp features a terrific cast - Jean Arthur, James Stewart, Lionel Barrymore, Edward Arnold, Ann Miller, Spring Byington - and a wonderful story about what's really important in life that is as timely today as it was more than 50 years ago. This is a keeper, folks. Break out the fresh video tape. (But be aware that KUED has scheduled the two-hour movie into a three-and-a-half-hour slot. Keep your finger on the pause button.)

The Three Amigos (7 p.m., Ch. 13) is a more contemporary movie comedy, and it clearly isn't in the same league as the Capra classic. But Chevy Chase, Steve Martin and Martin Short are fun to watch as Western movie heroes who try to take their screen act into the real world of banditos and desperados, and the movie features some fun screen moments - especially now that some of the crudities have been taken out for commercial TV.

Two series episodes are also worth watching tonight. 48 Hours (7 p.m., Ch. 5) reports on a dangerous new drug called "crystal," which can be made at home with easily obtained materials. And L.A. Law (9 p.m., Ch. 2) features interesting storylines about the homeless and the handicapped.

Elsewhere, Marie Osmond (7:30 p.m., TNN) gets her own hourlong musical special on The Nashville Network; Chuck Norris is A Force of One (8 p.m., Ch. 14); Maureen Stapleton guest stars on The Equalizer (8 p.m., Ch. 5); Burning Questions (9 p.m., Ch. 4) repeats Barbara Walters' report on "America's Kids: Teaching Them How to Think"; KOOG offers a curious prime time sports mix of Women's Volleyball (7 p.m., Ch. 30) and Bowling (8 p.m., Ch. 30); and the NBA Playoffs (6:05 and 8:30 p.m., TBS) continue - sadly, sans Jazz.