You know that Piaf was a stage name, right? Piaf = slang for sparrow.
Her birth name was Édith Gassion.
There’s 298 of us - rank is 62,775th.
Haha! Thanks for pointing that out. Evidently it is a real (and rare) last name though, even if in her case it wasn’t her real name.
My surname is pretty rare, only 4 of us in the world. My younger brother has the burden to keep it alive, no pressure but our father would really like to see a grandson with the name 
I knew a guy whose last name was apparently shared by 13 people in the world today (or maybe it was 23? Anyway it was under 30). His father was French and I believe the others with his last name were all in France (other than him and his two brothers). I guess an aunt who married into the family did some research on the family name and only found 13 people (or 23).
This is interesting, because my husband would qualify for this, except it’s also his dad’s and son’s name. IOW, my father-in-law, husband and son all have the same unusual and unique first and last name combo. There’s a lot of my last name in Louisiana; elsewhere, not so much.
I’m in the running! I’m not listed at all on Mongabay, and Whitepages had 12 listings. Of those 12, three were duplicates, and one was obsolete (a female relative who, upon marrying, changed her name.)
One of my friends from university had a unique (to her immediate family) surname in the UK. It gets 21 hits (or 11, when you click through to the results) in the USA on Whitepages. I suspect it would me more common in Spain, though.
My own surname is apparently ranked about 5,000 in America, so quite common. There are plenty of people with the same name as me, including a few I can find on Google with the same first, middle and last names.
In fact two must live within a mile or two of each other in Melbourne, Australia. I kept getting emails regarding some guy’s broadband account, so I tried to track him down on Google. I found what looked to be the right person based on his Google+ check-ins, but it wasn’t him.
I was born a Smith. When I got married I told my husband I don’t care if we get divorced, I’m keeping his last name.
My mother’s maiden name is very, very rare. When my grandfather came to New York form Puerto Rico, the ship he came on horribly misspelled his already not that common name. The name is so rare he didn’t even share it with his brother. We think he, his wife and his children are the only ones with the last name. His only son has no children, is about 60 now and it sure doesn’t look like he’s gonna have any kids.
Using the White pages linked above two people show up: My uncle and one unknown person in a state far away. This proves I don’t know what, since I am personally related to 2 other people with the name who are still living.
Now I wonder about that odd man out.
What a neat zombie thread!!
My maiden name is ranked 1,369 (23,756 occurrences in the U S) and there is a county in N Dakota named after my father’s family.
There are fewer than two dozen people alive worldwide with my last name. That’s partially because at one point a few generations back the name was changed form a (slightly) more common spelling for unknown reasons by an ancestor who used 3 or 4 spellings (and a few completely unrelated aliases) over the course of his life.
It makes it easy to get usernames and domains with my surname.