Black Markets exist on the Internet for in-game currency, time in the form of leveling services and pre-made characters, and items. The buying and selling of these goods and services is expressly banned by nearly every major MMO studio TOS, and while they seek to halt this illicit activity, it continues to be a growing problem within the industry.
The problems that game worlds face with the introduction of an outside market influence, such as real world currency, are many. Primarily at play, is the basic integrity of the organic in-world economy. Virtual economies are constantly evolving and changing under the press of the distribution and prevalence of game goods. Because virtual worlds do not have finite resource allocations as exist in real world economics, they face unique challenges and their integrity hangs upon a delicate balance. Altering this balance with an exterior factor, not accounted for in the design and development of the economy, can have drastic and dangerous impacts on that system.
Take a farmable game resource such as Iron Ore, for example. In a real world economy, there is only so much ore that exists. The prevalence of that ore is further limited by the processes and expense of mining it, and the distribution channels available to the miners. Now take that same resource under the scope of a virtual economy. The ore veins are spawn timed, with an infinite potential allocation of ore, limited only by the human hours available to harvest it.
In an encapsulated virtual economy, lets assume the player market settles on a 1G per 10 Iron Ore. Gold is earned at a specific time per Gold formula, with some players having more and some less, but the same basic exposure and availability to that currency. Now introduce real currency into the mix. 5% of the population purchase Gold, and are willing to pay 1.5G per stack of 10 Iron Ore, to insure that they get all that they need. Markets shift, and the in game currency is devalued.
Gold Farmers respond to demand, and since in game currency is a basically limitless resource, game economies become burdened with excess currency when farmers introduce the resource into the pool. More Gold in circulation means rising costs, without a compensating rise in 'currency-per-hour' availability for those not purchasing this external resource. Inflation that only effects goods, without effecting income.
There are countless other reasons why RMTs are a bad trend for the game industry, but the bottom line continues to be that they are a violation of the Terms of Service. Some argue that certain policies are overbearing or unnecessary, but when we agree to join a game world of our choosing, we agree also, to abide by the rules of that game's maker, despite how we personally feel about them. Those that bot, hack or cheat in other fashions are no more culpable than those that commit account fraud or participate in RMT activities.
This post began at this Nerfbat discussion thread.