It seems like most statistics about internet usage are gathered by people who don't actually use the internet. I don't get it. How do you measure that 14% of "t

It seems like most statistics about internet usage are gathered by people who don't actually use the internet. I don't get it. How do you measure that 14% of "time online" is spent on IM? Usually when I use IM, I'm doing a couple other things. For that matter, how do you measure "time online". That would make sense when people had dialup and would sit down and block off a chunk of time to be online. But with always-on broadband connections and 3G cards, it's much rarer to find a time when you're awake but not "online" in some capacity.