It's all very simple:
So why the powerful interest in this portion of human anatomy, anyway? Culturally-determined: If it's hidden, it must be interesting. A nipple on a stripper is, in general, less interesting than one on the housewife in the tank-top bending over the lettuce in the produce section of the grocery store.
I'm not judging anyone. I'll never forget when I was twelve, sitting on a beach in Hawaii, a beach that ran steeply into the ocean at that point so the waves broke powerfully and without warning, and saw a small woman from my hotel standing there, minding her own business when a sudden wave crashed down on her and Neptune swiped her bikini top. Thirty-three years ago, what, that's how old Christ got, right? The life of Christ separating me now from that event, and I see it so clearly.
So there's that. Which, together with the huge number of apparently bored people sitting at their computers, explains why my traffic doubled after I used the phrase "Condoleezza Rice nipple slip".
Also, I'm currently number two or so for the phrase "elf fucking".
Slow day here, as you can see.