Sex is the core of many celebrities’ personal brands. These popsugar people make a living being hot. They play out their lives with others who are just as hot. Megan, Brian, Scarlett, Ryan, Brad, Angelina, Gisele, Tom and the phalanx of usual suspects dance among their own kind. Their brand images are not just the output of stylists and press agents. Sex is the brand born out by these celebs’ behavior. It works because, like the core elements of all successful personal brands, sex isn’t just aped by these lookers. Sex is embedded in their characters, it’s authentically embodied and it’s relentlessly, consistently and clearly communicated, with well chosen co-branding partners.

Sex isn’t the same as “sex appeal,” which was a quaint notion that some people have a kind of “X” factor. Paul Newman projected that intense, undeniable magnetism. At the same time, he was a devoted married man for 50 years. Newman and his wife, the very elegant Joanne Woodward, enjoyed a very un-Hollywood life in Connecticut. In a then timely but now quaint simile, Newman told a too-inquiring member of the press that he didn’t need to eat hamburger out of town because he had steak at home.

Sex still sells

By contrast, today’s celebrity X-factor pretty much means X-rated, with proof of concept. We watch Kendra Wilkinson jump off The Girls Next Door to move on down the aisle with her baby bump to wed pro athlete Hank Baskett. If you haven’t seen enough Kardashians, more’s on the way as Kourtney sports a bump as the result of off-again, on-again relations with Scott Disick, or so says People magazine.

Good for them? Yes. As marketers and civilians alike know: sex sells. That’s why sex is such a powerful personal brand element. It sells movies, magazines, music and more.

Sex goes wrong

So how can a great personal branding technique as old as sex go horribly wrong?

This week another married man from Connecticut came forward to tell us he’s a victim of his sexiness. That unlikely man is David Letterman. Apparently, untold numbers of young assistants throughout the years find sex with him consensually impossible to resist.

Apparently, he regularly hires small armies of young women assistants, and in his public words has “creepy” sex with some of them. Letterman’s utter lack of contrition and just plain conscience about the lives he tainted, evoked the mindset of a plantation owner. The master knew whomever he choose to serve the family in the plantation house got a better job than most, and it was a job worth doing what it took to keep. Kind of like serving a production company owner and talk show star, and occasionally looking after his son.

When the story broke, I watched a clip featuring Letterman and one of his “favored” assistants. They were playing Letterman’s signature bit “know your cuts of meat.” It was a rude simile, given the situation.

In the bit, Letterman’s assistant, lucky to get that camera time, was cast in the role of trying to guess the piece of meat, as she looked at pictures of meat flashed on the screen. She played the ditz, got it wrong and everyone laughed. He asked her if she wanted to play again. Playing the patsy, she did. She never did get one right.

Some things are just really hard to watch.

This isn’t the dance of equals, like Brad and Angelina meeting on the set of Mr. and Mrs. Smith and leaving Jennifer to be America’s aging sweetheart. This isn’t watching Julia Roberts get serially engaged to one leading man after another until she finds settles on Danny for her happily ever after. This isn’t Tom making babies with Bridget and Gisele.

This isn’t even a reality show where people sign up to exploit their bodies and bad habits.

It took a celebrity to prove that sex can’t sell everything. Maybe even another season of the Late Show with David Letterman.