With all of the work Gulliver has done on his RE Primer, I thought it was about time we helped out on the FE FAQ. In this instance, I wanted to help expand on who's in on the conspiracy (or has been in the past) and what their motive is, as the information currently in the FAQ is rather lacking. Feel free to add to this!
Eratosthenes, Posidonius, and Ptolemy
The men that kicked it all off, by carrying out independent experiments in Ancient Greece that supposedly showed that the Earth was round and not flat.
Why?
We don't know, but it was probably money.
Who else is involved?
Everyone that replicates the experiment and talks about it to perpetuate the myth. Anyone who buys the basic equipment will have their costs refunded by the government and a free holiday to the ice wall for a long weekend.
The Ice Wall Guards
These guys are busy protecting the 78,000 mile long ice wall and whatever lies beyond it. Nobody has ever heard a squeek from them.
Why?
We don't know, but it probably involves money. To keep them all quiet, the governments of the world must be rewarding them well. To keep them happy, they probably have their own World of Warcraft servers for recreation, bars, casinos and brothels. If they weren't happy, they could cause havok in the rest of the world if they revolted. Computer simulations have shown that if they all jumped up and down at the same time, they would cause a tidle wave that would engulf all of the world's continents.
Who else is involved?
The governments who supply the soldiers, Blizzard entertainment, and all the bar staff, croupiers and prostitutes.
The Governments
This goes without saying, of course. Starting from ancient Greece, all governments were gradually coerced into supporting the conspiracy. All of the apparent disagreements over policy or ideology were faked or set aside in the greater evil of the round earth conspiracy. Saddam Hussein was heard to say on the way to the gallows, "Remember, infidels, that the world is round!"
Why?
Well, that's like asking why America invaded Iraq! It's money, of course! Maybe there are oil or gold reserves beyond the ice wall. Maybe the secret to eternal life is beyond the ice wall. Maybe there is lots of ice beyond the ice wall.
Who else is involved?
Everyone who works for the governments. If the governments are protecting oil reserves, then the oil companies must also be involved (potentially faking their oil extractions elsewhere or maintaining artificially high prices). The space agencies are obviously involved too.
NASA, ESA, RSA, etc.
All of the space agencies, both government controlled and commercial are involved, faking the sending of satellites and inter-planetary probes into "orbit". In reality, they are firing them into the sea near the ice wall.
Why?
We don't really know, but it must be money. The government is putting billions of dollars into these agencies, which is probably spent by the agency administrators on rewarding the people who carry out the Eratosthenes experiments, as well as their own trips to the the bars and brothels beyond the ice wall.
Who else is involved?
The scientists who create the interplanetary probes, which obviously never go anywhere. Satellite navigation companies. Satellite broadcasting companies. Richard Branson and his Virgin Galactic firm.
Airline Pilots
Most pilots would probably never claim to see the curvature of the earth, but they would certainly claim to navigate along great circle routes in both hemispheres of a round earth.
Why?
We don't really know, but it's probably money. After all, they can't paid that huge salary just because of the stress, long hours and the fact that they are responsible for hundreds of lives. They're paid to keep their mouths shut about the fact they travel at supersonic speeds in the southern hemisphere and that a route from Australia to Chile does, in fact, take them up the Western seaboard of north and south America and near to the north pole.
Who else is involved?
The airline companies, of course. The air traffic controllers. The passengers. People at ground level who have witnessed Boeing 747s passing overhead at supersonic speeds, leaving behind 747-sized sonic booms.
Australians
They would maintain to the world that the shape of their continent is approximately two times the distance east to west as it is north to south, as this fits in nicely with the round earth model. In fact, Australia is at least 4 times the distance east to west as it is north to south.
Why?
We don't know, but it must be money. They are probably too drunk and too busy having "barbies" to notice what shape their continent really is in any case.
Who else is involved?
Anyone else who maintains that the shape of their world is inconsistent with a flat earth. So, that means anyone in South America and Africa in particular. Most Africans, of course, do a great job in hiding the wealth that they earn from the conspiracy.
Scientists
Astronomers keep making "findings" about the universe that simply aren't possible in a flat earth. Solar observers keep showing computer generated images of the ball of fire they call the sun.
Why?
Money, of course. All scientists are secretly stinking rich, but outwardly only show the living circumstances of a research income.
Who else is involved?
Publishers of research journals. Teachers. The programmers who have written the sophisticated computer imagery software since the 1950s.