That's an expression ("The world is a handkerchief") I have often heard, and often found true. It means the world is a very small thing and it's hard for something (or someone) to get lost in it.
Here are two examples:
I went to school with this guy. We were never friends or anything. I had completely forgotten about him. One day, I was walking to the bus stop after teaching, and someone calls me.
It's him. This was roughly 15 years after the last time I saw him.
So, we start talking: he worked 2 blocks away from where I did. And 550Km away from our school, and in a 12 million people city.
He had lived until three weeks before in an apartment around the block from my own.
He usually went to the same cafe I did, in the corner of our streets, but he did so 90 minutes earlier than I did.
And we had never seen each other.
Then we did. On a third place, which was not related to neither of our jobs or homes.
I met Rosario on May 25th 2004. Except I almost met her in 1995 (or so).
I was telling her last night about an affair I once had with a girl that lived a ridiculous distance away from me (800km or so) and how I had last seen her in a congress of the FUA (Argentina's students organization) that took place in Santa Fe, where I was born.
That congress had one party (where I broke up with this girl) in my university's law school.
Well... Rosario was there. I don't remember her, but knowing the place where that party took place, I could not have been the whole night without passing 10 feets away from her.
In fact, I can't get out of my head a false memory of a girl looking remarkably like my wife sitting on a planter with a worried look in her face (she had had some issue that day), with a drink in one hand and a cigarette in the other.
I know I did not see her because I didn´t remember this yesterday, but... I ended leaving the party with another woman (oh, being 24, rash and pretty stupid... that woman was trouble). What would have happened if I didn't, and started talking with the woman sitting in the planter?