When applied to fiction, the term Lowest Common Denominator means appealing to as many people at once as possible.
So what does it mean when Lowest Common Denominator is applied to the genre of television?
It means most of the garbage that is on TV, like the Kardashians, Real Housewives, Bad Girls Club, etc. It is programming that appeals to the least intelligent viewers, but for some reason, smarter people will also watch it. Eventually, it dumbs down everyone.
And why in the world would Television Execs want to “dumb down” their audiences, on a mass level?
It's a name [lowest common denominator television] for a mass media production strategy in which programming is produced, not to create the strongest possible response, but rather simply to offend as few people as possible.
The idea is that material that creates a strong response, that is, which is very much liked, is also likely to alienate at least part of the wider audience. So you get a loud applause, but from fewer people.
By contrast, mediocre material, which does not challenge or criticize too much and so on, as long as it is slickly produced and provided in an invariably cheerful manner, will get at least some attention from a much larger segment of the total audience, even if it does not particularly impress any of them.
Mass media of course is mainly interested in just getting the highest number of eyeballs on the ads. It doesn't care about making the eyeballs especially interested in what they're seeing.
Here’s the related corollary to that programming philosophy …
What does lowest common denominator television mean?
Have the type of programs that do not require much serious thought.
What does lowest common denominator television mean to you — the Viewer?