The advent of radio drama, cinema, and in particular television created greater pressure in marketing to clearly define a product as either comedy or drama. While in live theatre the difference became less and less significant, in mass media comedy and drama were clearly divided. Comedies were expected to keep a consistently light tone and not challenge the viewer by introducing more serious content.
By the early 1960s, television companies commonly presented half-hour-long "comedy" series or hour-long "dramas". Half-hour series were mostly restricted to situation comedy (sitcoms) or family comedy and were usually aired with either a live or overdubbed laugh track. One-hour dramas included such shows as police and detective series, westerns, science fiction, and serialized prime time soap operas.
While sitcoms would occasionally balance their humor with more dramatic and humanistic moments, these remained the exception to the rule as the 1960s progressed. Beginning around 1969 in the US, however, there was a brief spate of half-hour shows that purposely alternated between comedy and drama and aired without a laugh track, as well as some hour-long shows such as CHiPs in the late 70s to early 80s. These were known as "comedy-dramas". Another example was The Days and Nights of Molly Dodd, which aired from 1987 to 1991.
These early shows influenced how general TV comedies and series (especially family themed sitcoms) were developed. They often included brief dramatic interludes and more serious subject matter. An example of a successful comedy-drama series that distinguished this genre in television was the series Moonlighting. It generated critical acclaim and was a highly rated series worldwide. Another example of a successful comedy-drama was the television series Eight Is Enough. The show was distinct, because it was not a comedy-drama in the traditional sense. It was an hour-long series that utilized a laugh track, which was very unusual, but is considered a comedy-drama for the fact that it alternated between drama and comedy.