“Show me a woman with a good three inches of cleavage on display, and I’ll show you a woman who, rightly or wrongly, has little faith in her powers of conversation.”
Well, I wouldn't presume to know what a low neckline says about a woman's self-image, but I have always found the display of cleavage problematic in the workplace. Whatever a woman may choose to wear to a party or to the beach is her own private choice; but what she wears to the office affects everyone there.
In Washington, the term "skinterns" was coined a few years ago to describe the bare-as-you-dare way styles favored by some female interns. It's mind-boggling what some of them consider appropriate or acceptable for office wear.
On the one hand, I am sympathetic to the interns' plight, recalling what it was like to try to put together a week's worth of business attire when I first graduated college. These interns are mostly college juniors and seniors who probably can't afford to go to Lord & Taylor or Macy's and buy a whole wardrobe of power suits and nice dresses (which will be out of fashion by the time they graduate, anyway).
On the other hand, the display of cleavage in the workplace is completely inappropriate and unprofessional. It's distracting and annoying. Even if you've got cleavage worthy of admiration, displaying it at the office will only incite envy among your female colleagues, while causing your male colleagues to fear that you're attempting to entrap them in a sexual-harassment suit. (Trust me, guys do worry about that kind of stuff.)
Please, ladies, reserve the display of decolletage for your disco dates, and save those strapless sundresses for Sundays in the park. Even if you want to draw the interest of some fellow at work, baring your bosom is not the best way to do it.
Remember: If you dress in the way that leaves nothing to the imagination, you'll only attract guys with no imagination.