Maybe you look very handsome !!!

may be the skin tone. chinese are jaundiced yellow color.

Skater, you're Chinese, aren't you?
So you're asking this in English, on an expat-centric website. Odd.

I agree with MMD. It's because of the handsome faces they see. Hah! Like mine. (Sure, sure.)

That depends, maybe because in small city in China people never saw a foreigner before. In Shanghai, no one cares.
And about the handsome part, just cannot agree~

Foreigners are the freaks in China's sideshow.

we're white monkeys 4 them. that's all. Xi'an is a big city, but they are stare anyway.

Well, other than the rudeness part, it deals with a lack of morals. They are curious but where does curious stop and rudeness begin, lets say about five minutes of glaring at you. I just stare back and make funny faces, then they ask me in Chinese whats wrong with me, so then I speak Chinese and to their astonishment a foreigner can speak Chinese. Ohh, the best one is when a Chinese man was selling corn, I bought one and he asked me where I'm from, I said America, and his response, Americans eat corn too. Oh my god, put a sock in it already. i didn't want to bust his bubble with watermelon.

For the same reason they can't help but gather around a fight or argument in the street: curiosity!

They know next to nothing about us, except the stereotypes they're fed from their amazing local news. Thankfully, being an ABC I don't really have this problem!