I think they're both very valid metrics -- but of different things. For example, I spend about 50x more time online than my parents do, and I think we need a m

I think they're both very valid metrics -- but of different things. For example, I spend about 50x more time online than my parents do, and I think we need a metric to capture that. But we also need a metric that points out that people who open up their computer once a day for 20 minutes to check email, pay bills, and read the news -- may have very different browser characteristics.