I nabbed this off of Yahoo Answers
According to Hope's research, businesses began "encouraging" American women to shave their underarms around 1915, when sleeveless fashions became popular. Harper's Bazaar featured an ad stating: "Summer Dress and Modern Dancing combine to make necessary the removal of objectionable hair."
According to the article the same thing happened to encourage women to shave their legs a few years before that. So apparently pre 1900 smooth shaved skin was not a sign of being feminine. That’s not the first time I heard that Harpers's Bazaar started the whole smooth skin thing for women. So what will change in the next 100 years ?
Just food for thought.