The W3C’s Web Performance Working Group is working on a specification to define 20 “fine-grained” metrics to measure the duration of just about every aspect of a web user’s navigation behavior. The W3C’s working draft of the Navigation Timing Specification is in the “last call for comments” phase. After being finalized, it will specify 20 measurements for every page visited. http://test.w3.org/webperf/specs/NavigationTiming/