Traders are social engineers. The successful ones are often social butterflies and make as many friends as they can possibly exploit. They buy everything they can possibly get a hold of as long as the price is right, and then they turn around and sell it for as much as they possibly can. They are the middle men for players who are looking for a quick profit and do not feel like waiting for the big score.
They easily amass the wealth of nations. They can change the tides of wars by providing access to their massive stockpiles of weapons, or they can start wars for profit. They hide their identities and sell weapons and ships to both sides of the conflict that they engineered themselves.
Those that are able to tame the markets of Eve-Online can do anything they please. They are great benefactors for players they think can turn a profit for them. They influence every players life by providing a steady flow of materials. They are the grease that lubes the Eve-Online economy. The universe is yours! Take it.