As an avid traveler, I've been relying on friends' friends wherever I go. I could see your app flying!
scaling friends of friends, combined with geo location, timeframe and interest tags has been an engineer challenge but we are starting to look into other graphs like above
Also, what makes this site any different from simply utilizing one's social graph directly on Facebook, Twitter, Google+ etc? Why would one need your service when he/she could just tell their Facebook friends, "Hey everyone, I'm traveling to Rome this week. Does anyone have friends there I should meet?"
I think if you have a solid answer for this, it may need to be communicated more clearly on your landing page.
On the upside, good job with the site design. That part is pretty solid for a first go.
Your profile info: birthday, hometown and location Friends' hometowns Friends' locations
I'm taking a year off work and traveling across the world for 2012 and would love to use the app but I see no reason for it to want that information.
My friends are already my friends on facebook, so I don't need them on the site, I need to find new people.
Everytime you recommend a friend from a certain city, that friend (even if they are not using the site) will be visible to all your other friends using the service. They see that this person was recommended by you.
You too share the same benefit. You gain all your friend's recommendations. Again these people have been handpicked and selected. I know I have 10 friends in China, based on some people I have added from my masters program, but I would never really recommend them.
The idea looks really good and I've long wanted such a thing. In fact, I'd use it today if I could sign in. But I'm not on Facebook and know that there's no point joining Facebook just to sign in since they "need" your social graph and mine would be empty. So, no point doing that.
I'll bookmark the site and drop it into my "visit monthly" folder. On the visit that it doesn't require Facebook I'll sign up.