1. A computer implemented method of determining an aggregated web analytics value, comprising: storing in a first data storage medium a series of episodic values, each of the episodic values being associated with a respective predefined time interval; storing in a second data storage medium a sequence of first level aggregate values, each of the first level aggregate values aggregating a respective set of consecutive episodic values; and receiving a request to provide the aggregated web analytics value from a selected range of the predefined time intervals; determining, in response to the receiving, a set of one or more episodic values within the selected range and a set of one or more first level aggregate values within the selected range, wherein a first period of time for the determined set of one or more episodic values is not included in a second period of time for the determined set of one or more first level aggregate values; and generating, using one or more computers, the aggregated web analytics value by retrieving and summing the determined set of one or more episodic values from the first data storage medium and the determined set of one or more first level aggregate values from the second data storage medium.