6 degrees of separation

I grew up in Southern California (1)
I have a childhood friend named Cheryl (2)
She has a younger sister named Carol (3)
Carol went to New York to work after grad school.
Carol met and married Brook (4) (who grew up in a cabin in Colorado).

That was some time ago.

Turns out Brook had an Uncle and Aunt who lived in our small town (5)

We looked them up.

His cousin still lives here (6)

How could our world be so humongous and so small at the same time.