"According to Bob, short copy performs better when there is low perceived risk, low cost, and low commitment. Also, when the customer has an emotional, impulsive, and “want-oriented” motivation. In other words, if you’re looking to write high-impact copy for concert tickets, designer shoes, or mp3 players…keep it short. Bob states that long copy is the better performer when there is a rational, analytical, need-oriented motivation. Think consumer insurance products or many complex B2B offerings."

http://conversionxl.com/4-cases-where-short-home-pages-outpe...