“Everything in the world is about sex except sex. Sex is about power.” ― Oscar Wilde

They were right then as they are right now, sex sells (c) and it's a shame they didn't own the copy rights.

It's true that sex is a powerful motivator that works on all humans on a sub-concious and instinctive level.  When used within the creative confounds of the advertisement messages that are hard to resist are sent and many are hard to ignore.

Hotels, if you've every stayed in a bad one you'll know there is nothing sexy about them, but take the hotel idea and cover it dripping in the sweet sticky glossy sheen of sex and soon you are atrtracting guest like bees to honey.

The above is an advertisement for a hotel in Las Vegas.  It plays heavely on the themes of S&M and bondage. It's very visually based, which for men sex is, and it capitalises very nicely on the recent interest in the little known and tabboo world of S&M that has come to the fore with the recent
50 Shades of Grey book and movie franchise.

Sex and power, power play 

The more traditional red-blooded american male perhaps is a little more traditional and he therefore is attracted to the more less niche area of sex.

The below advertisement uses no wording at all except for the name of the brand at the bottom of the advertisement.  It reallys wholly on the visual effect to convey meaning.

The female model, posing in a provocative stance, in an erogenous display.  The male character assuming the role of the powerful boss his feet up on the desk indicating a blase and casual demeanour.