Since the advent of the Internet, companies have tried to develop web metrics to monitor the use of their site. Consistent with offline performance measures, web metrics have to relate to objectives as established in a web strategy. However, due to the newness of the medium many companies at least initially lacked clear Internet objectives [20, 21]. Compared to offline operations, the availability of data was much less of a problem. Clickstream data are widely available, as it is stored by default in server logs and through page tags