Sex sells. I’ve carried that common wisdom around so long, I can’t remember when the idea was new to me. Wanna sell your product? Use sex! Of course, the adage doesn’t really mean “sex” or ads would look very different.
It was really sex that sold, we would see more, well, SEX. Fornicating, screwing, messing around, getting taken to church. Two or more people doing sex as a verb together. But that’s not what we see. What we see is naked women, or parts of women.
What’s more, recent studies suggest “sex” (femme nudity) doesn’t actually increase sales or the effectiveness of advertising. Sexual content in ads or in surrounding media content interfered with cognition and memory in tests, and people were less likely to remember a brand name if they’d been exposed to sexual or violent media (a combination often used together in “sex sells” style advertising.)
Sexual content in advertising also puts off many potential customers, for a variety of reasons. Some find the highlighting of unclothed femme parts objectifying. Some are annoyed by the obvious manipulation behind the titillation. Some think nudity has no place in the public sphere. Entirely different populations of shoppers become less likely to buy a product when “sex” is used to sell it.
Most importantly and devastatingly, being exposed to repeated images of objectified female bodies influences children of all genders to devalue women and girls. There is also a strong correlation between advertising exposure and negative body image in teen and preteen girls. Even if “sex sells” were true, we should ask about the cost. Is the emotional and physical well-being of girls a price they should have to pay for the profit of the ad agencies and their clients?
We say “sex sells” but we don’t really mean it. Or else we’d see two male models kissing to advertise beer and we’d see male nudity as often as female nudity. Go Daddy ads would feature men in skimpy costumes and Herbal Essence ads would end with screwing. “Sex” isn’t what’s being sold. “Sexism” is.
I highly recommend the documentary film series “Killing Us Softly: Advertising’s Image of Women” by Jean Kilbourne for more information and insight on this topic.
Angie's Anti-Theistic Thoughts 
I agree with the idea that when people say “sex” they usually mean women. Female sexuality. Femininity. “Beauty”. It’s interesting where you note the different reactions to using sex (i.e women) to advertise and promote. I remember a while back reading the comments of boxing fan, saying that he hated round card girls, implying that they were taking the attention away from the boxers. Like “This is for men only, no girls, not even sexy ones”. You could probably debate which is worse, a shallow appreciation of women or no appreciation at all. I’ve noted the same thing about books, films and other media. Is it worst to have no female characters or to have female characters that kinda make women look bad?
I could also bring up religions where women are expected to cover up and sexuality is heavily discouraged. So there are people who want explicit female sexuality and others who want next to none at all. And neither is particularly appreciative and respectful of women. Certainly women’s bodies are used to exploit people. Sometimes by men, sometimes by women, sometimes by women using their own bodies to exploit. Other times I feel the exploitation isn’t intended, but people react badly to female images. Some people of course look at almost all images of women with sexual lust and without respect. Others may oversensitively feel they are being exploited, when perhaps that isn’t intended. There are I think a lot of cases though where a person can’t really plead ignorance. They had to know the effect their images would have on some people.
Another point is the discouragement of male sexuality. By that I mean, men showing their bare flesh or wearing tight clothes that shows their body shape and shows that men too have a degree of “voluptuousness” that many men hide with baggy clothing. Rock music has of course been a field where the men have embraced this type of sexuality. Beginning with the likes of Jim Morrison, Jimmy Hendrix & Robert Plant and moving on to more androgynous men like David Bowie, Marc Bolan(T. Rex) and Freddie Mercury. As I said, female sexuality is also discouraged by some, but it’s harder to think of male rock stars as being as being used to exploit audiences, though I’m sure there are cases where they were. Personally I think that rock music has given men and women the freedom to express themselves, sexually and otherwise. I think some have gone too far in more recent times and been exploited, exploited themselves, or exploited others.
Angie, you are correct! It’s sexISM!