@frank: you'll get one coin on every move, not just if you pick the right one. the calculation from bezzle is correct
Are you sure?
Lets assume there were 400 people who take part.
This means, that 200 games are at the same time and all games are on the wall with a projector?
But maybe you are right and I am mixed up with the "Play for Privacy Go Voting Games" from the Whitepaper:
"Players join teams and are rewarded for voting about where their next stone will be placed."