Does she look like...someone you know?

I often heard this from someone I've just met.
"I have a classmate who looks like u..sure u're not in my school?"
"You know, you look like someone I know..."
"Gosh, you look just like my friend!"
"Are you one of my students? I got one who looks just like you."
"I think we've met before. Your face looks familiar to me."
I swear, I often heard it from people that it made me wonder 'Do you? Does she? What does she lool like, actually?" cos I'd like to know. First, you might thought that it was some pick up lines to break the ice so that converstation can go smooth, but I often heard it from women.... I've heard it more than 20 times and it still surprises me!
I wonder if there's really someone who looks just like you. And what would you do if one day you bump into each other...wouldn't it be weird? But, if it ever happens to me at least it has proven the words people always say to me...that there is someone who looks just like me, and I, this 'someone else's twin' would be glad to meet someone who looks just like her, other than her own sister.
Just a curiosity. *wink*