Myself, clearly. I can even bet that none of the 6 billion plus people know me better than I do. 
Bits and pieces of computers and networking. Random assorted games. Chinese and Chinese history. Bits and pieces of science - particularly mud puddles after spring rains (j/k ;)).
Honest answer: not a damn thing.
Mamapotomus!?!?! Yay!!
Thought you’d pulled up stakes.
Germanic linguistics, specifically the Western and Northern branches. I bet I know more than 99.9% of the population does about that. And while still on that thread, acoustic and articulatory phonetics, in that I can pronounce pretty much everything on the IPA chart, except for perhaps the ingressives and a few specific articulations. Oh, dear, the geekiness is leaking again…
Any others… Nope, unless you count Weimar-era Germany, Victorian-era England and countless bits of historical and literature-related trivia. But those probably don’t qualify for the 99.9 percent stipulation.
And astro, as mud puddles go ( 
), you do a pretty damn good conversation.
Quality of and treatment methods for urban stormwater runoff. You know the water that runs off the parking lots when it rains? There’s a whole industry built around cleaning that stuff up.
astro
You’re far too modest.
Apologies to the OP. I didn’t complete my post properly.
I’ve been cabinetmaking for 22 yrs. Like Ringo, I ran my own company for a number of years. Also like Ringo, I let the job define me.
The real reason I think I gained expertise is desire. I wanted to learn about cabinetmaking. I’ve had arguments with a few friends before about that. I say that any person will be better at any given discpline if he/she desires it. I’ve actually had a friend take the opposite side, saying, “Motivation does not matter.”
I think he’s crazy! Any person who desires (insert area of expertise here) will strive to be the best. Doing it for the money, or parental approval will never produce the same results.
FWIW I didn’t read the 99% bit.
Me in the one percentile of expert sailors? Ha! It is laughable!
Me in the one percentile Opera expert business? Laughable!
Movie Trivia use to be *my thing *. Since kids, I’ve slacked off way far, but I could still hold my own.
**Regency, England **
**Stain removal from carpet ** ( vomit works better than Resolve, just so you know.)
What if you’re determined not to vomit?
The secret is to pick an obscure field. I know more about recumbent bicycles than 99.9% of the population. That comes from reading all (or rather, both) recumbent-related publications for a couple of years.
Not even yourself?
Seriously, though, there are 6 billion people on earth. 0.1% is 6 million. For many fields, there aren’t that many reseachers in them.
The associative interpretation of the McCollough Effect: I wrote my dissertation on it.
Heroin dependence pharmacotherapies: I worked with them as a post-doc.
Potential reduced exposure products for tobacco users: I study them now.
Bridge load rating.
Bridge Management Software- in fact I call myself the Pontis Pilot. (You won’t get that unless you’re in the business)
Comic books
Pithy, appropos, sacreligious, I LIKE it!
I am the world’s leading expert in Military Codewords (Desert Storm, Overlord stuff like that). I have the only published book on the subject.
Masonic history also.
My ass you don’t! I’ve seen you on several boards, talking about evolution and you seem to know a great deal about it, and if you don’t know more than %99.9 you know very close to that number.
Shoot, whenever I see a post that’s anti-evolution, I almost expect you to come along and straighten out the ignorant person.
Food, and all aspects there-in.
I am a independant gourmet chef specializing in catering musical events and have been the premier chef for the Phoenix Sympony Orchestra, Providence Symphony Orcestra and am the sole owner of Mystical Palate procurer of fine foods. Owned and operated the business for 22 years.
Tapas anyone?
The history of 19th century western North Carolina. How? Grad school, independent research, working in history museums, and hours upon hours spent in the archives. Why? Because, really, who wants a high-prestige, well-paying job when they can be a historian?
Anglo-Norman historical writing in Latin in the 11th and 12th centuries.
Amazingly enough, I am not unemployed.