A virtual economy (or sometimes synthetic economy) is an emergent economy existing in a virtual persistent world, usually exchanging virtual goods in the context of an Internet game. People enter these virtual economies for recreation and entertainment rather than necessity, which means that virtual economies lack the aspects of a real economy that are not considered to be "fun" (for instance, avatars in a virtual economy often do not need to buy food in order to survive, and usually do not have any biological needs at all). However, some people do interact with virtual economies for "real" economic benefit.