Before I was working, mine was very much like the European one (and I am in Europe, so...). So was the internet usage of a bunch of friends. Sleep in the morning, get on the net in the late afternoon and then go to bed somewhere around 6am - some people went earlier, though, so the 3am dropoff seems about right.

Now I get on the internet at 9am, stay on till about 6pm. Sometimes I use the internet after that, but often I don't.