Are you absolutely sure this is how it works? I have a 1 page website where the average time is 1:36, shouldn't it stay at 0 since the users are not clicking to other pageS?
Maybe I'm misinterpreting something, but the way I understand it, the last (or only) page of a website is handled differently. If it's a single page website with a demo download, and someone downloads the demo, then the time between pageload and the download would be counted. If there's a Flash movie, the time between loading the page and playing the movie would be counted. It also looks like you can come up with your own custom events to track, maybe like clicking an outgoing link?
I've never seriously used GA so take my interpretation with a basketball-sized grain of salt.
Before changing the site to a multiple page site, I was averaging 1.2 pages/visit. Again with a 1 page site, but I would develop on the server so I figured GA was picking that up. Since changing to a multiple page site my pages/vist is 2.55 and my average time on site has increased by like 20 seconds, which seems a lot. Maybe people are on 56k, haha.
But does anyone actually know? I can see from this thread that plenty of people thought they knew, but it seems nearly half thought it worked one way, and nearly half thought it worked the other way.