What is "mudflation"

n. (context economics informal English) The gradual decrease in the value of existing virtual goods in a massively multiplayer online game as new goods are introduced.

Mudflation, from MUD and inflation, is an economic issue that exists in massively multiplayer online games. Mudflation occurs when future additions to (or even just continued operation of) a game causes previously acquired resources to decline in value. This can take many forms and have many causes, including new items introduced by an expansion pack, fundamental imbalances in the in-game economy, or even spread of information that allows a previously rare resource to be acquired more easily.