Yes I read that Jiwoo majored in dance at "Shui Yuan Nu Zi Da Xue" (Chinese for Shui Yuan Women's University, I don't know the Korean version).
Agree with Jayne that her posture and graceful body language could have been boosted by her dance background. I don't think she has really showed off her moves in her drama/movies so far right? (No, the little boogie with Taehwa in STH doesn't really count) I mean, serious dancing.
I do remember her in the Joinus ad. Woww.. Talk about sinuous!
Also in the making of the Paroma ad she danced around with the conductor's wand, and got NG from director who thought some of her movements too Sexy! Ha ha ha ...