The idea is to help advertisers distinguish the minority of heavy Web surfers from the masses of less active users. There categories will
created using time-based criteria. The "heavy" category contains the 20% who spend the most time online; "medium" will contain the next 30%, and "light" the remaining 50%.
like Nielsen/NetRatings report average site usage using their total audience, which some believe is misleading, because heavy users bring those averages up. For example, comScore says heavy users
spent almost 97 hours online in May, while light users spent just 3.6 hours, yet the resulting average is 28.8 hours spent online. The measurement firm points out that heavy users tend to spend more
time on each page and visit a larger number of pages than light users.
Bob Ivins, ComScore's executive vice president, says the changes could encourage advertisers to shift their spending habits.