KDE will indeed probably be more popular with people who use a computer
regularly (for example those working in offices) and Gnome is more for the
casual grandma who checks mail once a month.
Then again, that might change. Gnome really needs to change stuff to get
development going again. Seeing how much time many KDE devs spend thinking
about usability makes me expect KDE to start doing much better in that
regard. 4.2 is already a clear testament to that, btw.