Nielsen/NetRatings, one of the leading online tracking services, have announced that they will be changing their method of measuring website popularity by moving from the rankings based on the page views to one that records how long visitors spend on a site. At a time when the measurement of web usage is under much review, this move comes as online video and other new technologies are making page views increasingly less meaningful.

Nielsen's user panels do already measure the average time spent and average number of sessions per visitor for each site, but it is now expected to start reporting total time spent and sessions for all visitors to give advertisers and analysts a broader picture of which sites are most popular.

The traditional measure of page views reflects the number of web pages a visitor sees from a site, although sites like Yahoo are increasingly using Ajax software to improve users' experience by updating data automatically and continually, without users needing to pull up new pages. As a result, page views decline and don't necessarily represent site usage, plus sites like YouTube where users watch online videos can affect the data on site usage.

This new measure will still have problems, since time on a page may not necessarily reflect the user devoting attention to the site. Google is also expected to drop down the rankings since its main objective is to get people off the search engine as soon as possible!