2010

A trend is something that becomes popular within mainstream society over a relatively long period of time (more than a few years). It is the direction of a sequence of events that has some momentum and durability.

The number of people involved in a trend and its duration will determine whether it's a "fad", a "craze", or a macro trend.

A fad is a trend that dies down significantly within a few years. fads-that-need-to-go-away-in-2009/

A craze is a product, idea, cultural movement, or model that gains popularity among a small section of the populace then quickly migrates to the mainstream. mainstream

Crazes are characterized by their lightning fast adoption and swift similar products, ideas, cultural movements or models.

Crazes and fads are also characterized by their unusually high interest and sales figures relative to the time they are active in the marketplace, as compared with other similar products, ideas, cultural movements or models