Fad:
Basically, a fad is a popular practice or interest followed only for a short time with exaggerated zeal, angelic, or enthusiasm. A fad happens when we cry "Oh, I need that!" even if it's not something that ever crossed our mind to own, have or use before and where it doesn't meet any particular need in our life. Fads happen in all walks of life but the more ephemeral, transitory and prone to needing replacement or updates, the more likely it is to be a fad. Fad usually appears in a single industry and rarely crosses over into others.
Ex 1: Remember those sweaters/pins/scarf’s that had your initial embroidered on them. They were popular about 5 years ago. You looked outdated if you wore it 6 months after you made the purchase.
Ex 2: DSLR Photography
Ex 3: Faded jeans
Trends:
Trend is based on consumer needs and lifestyle changes. Products that are born out of a trend are made specifically to meet new consumer needs and behaviors. Trends start with the seeds of change and slowly grow into new directions impacting both products and entire industries. Although initially, product sales at the beginning of a trend may start more slowly than with a fad, sales increase along with the growth of the trend and its adoption by the mainstream.
Ex 1: Skinny jeans. They first made their appearance a couple years ago. Some people bought them, the celebrities started wearing them, now nearly every teenager and young professional has at least one pair. - Ex 2: Social networking
Megatrend:
A megatrend is a large, social, economic, political, environmental or technological change that is slow to form. Once in place, megatrends influence a wide range of activities, processes and perceptions, both in government and in society, possibly for decades. They are the underlying forces that drive trends.
Ex 1: TECH LIFE (A critical driver of this megatrend is the fact that