If you understand whats going on with the economy now, its pretty similar to what happens with gold farmers.
An external source is injecting massive amounts of wealth into the game economy. The end result is inflation. Items become ever increasingly expensive since gold becomes so 'easy' to come by.
Additionally, it screws over the common joe who doesnt believe in paying to get an advantage in an MMO game. He cant compete with people who buy money with real money. In most cases he is either forced to quit or keep up with the status quo.
Oh and its morally wrong to some.
Thats about it.
