Pseudonym parties may have a role to play here. @johan-nygren has ideas on how to solve the proof of unique individual problem.

Oracles seem to be part of it and pseudonym parties the other half.

What actions do you have in mind @ned, can you give an example?  I have thought a little about it but still think it could be gameable..Anyhow Oracles sounds interesting.

1st thanks @ned for steemit!

I'm fairly new here so don't fully understand all the concepts.
> prove they are a single person using only a single account
+ Will there be a particular reward of some type if someone proves they are...?

Being a webmaster since about '95, I totally understand why this is important.
+ I had a forum going back in the 90's and this guy created a second account, started an argument with himself, convinced himself he was correct and then pretended to now support the original membership.
  + All because he held a view that most people disagreed with. He would then post as the 2nd account telling people they should listen to the first account.
  + All quite deceptive.
    + When I discovered the situation, I booted him from the forum. And then, I caught heck from quite a few of the very same people he had so blatantly deceived.

So am I correct in ***ASS***uming this is important to help prevent deceit and fraud?
+ Or is the more important aspect to help prevent gaming the system?
  + Or is there another reason that I don't know to ask about, since I'm a newbie here?

++++++
Second question...
Won't this also put a stop to people creating a second account to create a group?
+ I've seen many curation groups, resteem groups and the likes.
  + Groups seems to be a valuable asset for the Steemit platform going forward.
    + Does the future hold a way to create groups, without causing a problem with the "single person using only a single account" verification?

++++++
One last question.
Wouldn't another reason to create a second account, 
be because you want to have a business account?
+ either real world or online business.
  + that would become an asset of the business.
  + and transferred to someone else if the business ever sold.
    + Does the future hold a way to create a business account, without causing a problem with the "single person using only a single account" verification?

++++++
Or am I way off base in asking these questions?
Am I missing some basic premise?