Looking at my desktop at the moment, I've got three Mozilla windows opened at the moment (just closed a fourth), each of which have a few tabs open. Mostly this is just a convenient reminder of pages I want to read when I have some time.
I used to use konqueror. Having Konqueror 30 icons on the desktop at once was a pain, and encouraged me to read through some of this stuff. With a handful of tabs open, I don't see as much stuff to be read, so I have an easier time leaving it for later perusal.