Risks

Since buying or selling in-game gold or items for real-world money is against the official "World of Warcraft" rules, players caught gold farming or buying gold can have their accounts permanently removed from the "World of Warcraft" servers.

Motivation

Earning gold can be a repetitive, sometimes tedious task. At high levels, where characters sustain heavy equipment damage and require powerful items on a regular basis, earning enough gold for upkeep and advancement becomes extremely time-consuming. This leads some people to try to circumvent the system by paying others to earn gold on their behalf.

Gold Farms

Gold farms are businesses centered on farming and selling "World of Warcraft" gold for real-world money. They are usually located outside of the United States--stereotypically in China, where inconsistent regulation and low cost of living make it financially feasible.

Chinese Gold Farmer

The "Chinese gold farmer" has become an Internet trope as gold farming has grown in popularity. It refers to "World of Warcraft" characters who obviously engage in endless grinding for gold, do not cooperate with other characters to complete quests and make frequent offers to sell gold or cheap items.

Academic Significance

Gold farming, along with many aspects of the in-game economy, accurately models real-world economic patterns. Some economists have started to study the "World of Warcraft" economy to learn more about how to predict economic trends in real life.

Source:

World of Warcraft Official Site