Evhead just reminded me of a really excellent book — The Tipping Point, by Malcolm Gladwell. The book covers trends, why they happen, why they reach a certain point and die down. For instance, when Hush Puppies shoes suddenly became hip again cause all the cool people in NYC were wearing them. Months later, the company reports a record amount of sales out of the blue. Just one example of many from the book. A good read.