 Determining why one person engaged in a desired action and another did not has long been a topic of interest in sales, where measurement of conversion has always been possible through sales data .In contrast, marketing has been mostly concerned with targeting with the masses, and the results of marketing have traditionally been more difficult to accurately measure.With the internet, it is much easier for marketers to collect data for analysis and evaluation in order to understand and demonstrate the effectiveness or ineffectiveness of their efforts and to make changes to improve them.