1. A distributed data collection system for collecting website usage data, comprising: a plurality of data collection nodes, each comprising a clock, each data collection node for: receiving, via a network connection, client requests for elements, each client request including data from at least one client machine, the data representing website usage; locally storing the received data; associating each received client request with a time stamp; and responsive to occurrence of a predefined trigger event, attempting to transmit the locally stored data; wherein the clocks are synchronized with one another; a data collection node selector, for dynamically selecting, responsive to current conditions, a data collection node to receive each client request and to collect the data included in the client request; and a master processing center, for: receiving collected data from at least a subset of the data collection nodes; sorting and aggregating the received data according to the time stamps to generate a set of events describing website usage; and performing statistical analysis on the set of events to generate a report comprising website usage statistics; wherein: responsive to failure of an attempted transmission, the data collection node retains the locally stored data and the master processing center flags the corresponding aggregated received data as incomplete.