These days, in fact, no topic seems to animate cable programmers and advertisers more than the new genre of advertising they see evolving, based on cable's unique features. The advertisements, which have been labeled variously as ''informercials'' or ''adformations'' and could range in length from a few minutes to several hours, would weave feature material into a sales pitch for a product. For example, Singer could underwrite a half-hour show on sewing at home, or Dart & Kraft could fill the time with recipes for summertime cooking. ''If the Kraft logo is behind the presenter during the entire show, in reality it's a continuous commercial,'' says Mr. Dann.

''Propaganda masquerading as information'' is the reaction of Peggy Charren, president of Action for Children's Television, to such proposed programs. Unless there are sufficient safeguards, viewers - especially children - may find it difficult to distinguish between the program and the advertisement, says Mrs. Charren, raising the specter of ''30-minute toy-store shows.''

Furthermore, while Bristol-Myers maintains that the company will not interfere editorially, critics say that the use of sponsorship could make cable programmers more vulnerable to censorship or control by advertisers, particularly in light of recent efforts by organizations such as the Moral Majority and its offshoot, the Coalition for Better Television.

Advertisers and cable executives disagree. Cable's relatively low operating costs ensure its independence, allowing it to ''sell fewer commercials and still make a profit,'' says Andrew Goldman, vice president for new service development at Teleprompter.

Mrs. Charren also voices concern that advertising could adversely affect cable programs even more fundamentally. ''When cable first came on the scene, one of the most important points it made was that it was a non-commercial alternative to television,'' she says. ''Now advertisers are saying, 'Here's another place to think of on a costper-thousand basis.' '' Consequently, she believes, it could become more important to attract bigger audiences, and narrowly focused programs, such as shows for early readers, might be abandoned.

Cable executives counter that their smaller, targeted audiences - the focus of cable's ''narrowcasting'' on its multitude of channels, as opposed to the broadcasting of over-the-air TV - will actually help sell time to advertisers. ''Broadening would negate the one thing we have for sale: our small, upscale market,'' says Mr. Cox of CBS Cable. ''To stay alive, we must preserve our premium audience.''