My surname is shared by fewer than 15 people in the US; if you account for the spelling variation when it was Anglicized from Cyrillic, it jumps up to less than 50 at most. People often assume I must be Asian if they only see my last name before meeting me.
My grandfather graduated college, but neither of my parents did. I’m the first sanguinal child to pursue their master’s degree in my family.
My surname is one of the most common in the US, but I am not related to one other person by blood in the whole country.
I am one of the few people in the world that has repaired a specific type of nuclear reactor, underwater.
My partner and I both have unique surnames for the state we live in.
I’m the only person in this state to have owned 2 of the breed of dog I have.
Where I’m from, where I live and what line of work I’m in narrow down the possibilities to one - all details I’ve shared here on the board.
My surname is very similar to the brand name of a common medication.
I don’t think that brand existed when I frequented playgrounds because it could have led to some teasing, but I also count my blessings that I’m not a member of the Viagas family - the potential for bad jokes is fortunately not quite as great with the sort of medication my name resembles.
Although my dad is the youngest of 5 siblings, I am the only grandchild with the family surname. All of my uncles had daughters and my male cousins were from my aunt. Sort of a shame I aint ever gettin’ hitched.
I am one of 3 people who work at my company. Only one of 2 who have been here for the company’s entire life.
I still have my tonsils.
I’ve posted this before, but my ears are not pierced. Never have been.
I’m 38.
I have a selectively eidetic memory- mostly for numbers. I once scared a boyfriend off after being able to rattle off his SSN after hearing it spoken once, months earlier. I would make a really good identity thief.
My surname is 2 syllables, the first of which is slang for copulation here in the U.S.
I have swum (ooh yay not often I get to use that tense!) with sharks (on purpose), been stung by a stingray, chased by a baracuda, and swam face first into a rather large jellyfish (the bell, not the tentacles). I held another jellyfish in my hand once (casseopeia sp?). I have no fear of anything in the ocean, although alligators and watersnakes terrify me.
41 here, never pierced.
You would recognize my mother’s maiden name. It might cause you pain. It may have done that already.
The details I’ve shared in the board about job, gender and location would be enough to identify me.
Anybody with my paternal lastname is related to me. The lastname has three words; some second-sons dropped two of them, so there are also people whose lastnames aren’t “exactly” mine but who are family. They just have to dig deeper to prove it. The oldest “secondary branch” that has kept the whole thing separated in the XIII century, but because they lived close to the main branch we kept running into each other.
The combination of my forename and surname is unique within the U.K.; my full name is, I believe, globally unique.
My father and I share a birthday (Nov 16), and my sister’s is the day after ours (Nov 17). My mother’s birthday is only 10 days before mine (Nov 6). November is an expensive month.
Also, my stepmother and my fiance share the same birthday (March 3).
What’s unique about me? I’m the only one of me!
I am the only high school student to have interviewed the creators of Myst, the computer game, though that was quite a long time ago and that distinction may well have been gained by others by now (I doubt it, though, they’re a secretive bunch). I’m still proud of it, though. 
I am the only member of my family (blood only, not including by marriage), who has not only not gone to college, but who was kicked out of high school. Despite that, I have a career and (if such things matter) make more than most of said edumacated relatives… which is always a sore point with them. 
In the category of ‘makes me unique, but useless for identifying me’: I possess an uncanny sense of duration and direction, all of which piss my wife (and others) off to no end. I have never been lost and would go so far as to say that I cannot get lost in the first place, barring deliberate acts such as someone kidnapping me or whatever.
[ul]
[li]I’m the first military officer & helicopter pilot in my family[/li][li]My grandfather on my mother’s side played for Cab Calloway[/li][li]Until 2 months ago I created projects for, arguably, two of the most influential people in the world. [/li][li]My middle name always throws people for a loop. And usually, when my full name is written out they mistake it for my last name.[/li][/ul]
My left arm doesn’t bend all the way out anymore because of a fight.
My Uncle and I have the same birthday. 19 years apart.
I made a significant contribution to the practice of Anti-Submarine Warfare.
I’m the only person to be undefeated in a certain online game, and that’s the first thing that comes up when you Google my real name. (Of course, I dropped out of the second game I played when I didn’t have time for it but that doesn’t change the fact I was NUMBER ONE for a good couple years.)