One of my web sites is about a software program. It showcases the work done with it including some "the making of..." something, a great number of tutorials and a forum.
A visitor would normally stay on the site from several minutes up to 2 or 3 hours.
Yesterday, a visitor who had made a few short visits in the recent past had obviously decided to explore the site thoroughly. He spent a whopping 7 hours uninterrupted on the site, except for what must have been a 20 min. dinner break.
From the time span between each page viewed I could tell that he was either attentively reading a page or taking in a tutorial and not just flipping pages forth and back without taking in one word as some visitors do.
Need I say that I'm chuffed, it certainly makes it all worthwhile.