besides the legs, I thikn it is your use of having them in the brightest part of the image to really set the image in motion.
You may like this flickr group for inspiration. The Brightest Spot I may start a thread for images that use this composition technique combined with reflective light images to see what DPCers come up with, I will let you know. :)
As per my usual, as I am late in commenting I won't read others comments so forgive me if I am repeating what has already been said... I noticed you put odd crop.. I think it is perfect.. the guys looking at the girls add so much to this story.. and your pp is dead on!
I like the square crop, but perhaps a little more negetive space at the top might help if it feels a little awkward. In any case those legs will attract attention wherever they go!!
I really like the b&w white here, and the expressions are priceless.
I noticed the legs first too. hmmm. Also, I love the couple in the background, they are looking over too. Probably they spotted the boots/legs too. Square crop works for me.
Indeed..admittedly her legs were the first thing I noticed...nice. The background in shadows accentuates the happy moment they are sharing as do the onlookers... Nice!