"The KDE community dubbed KDE 4 "The Plasma Desktop Shell." One
look at the splash screen and the Plasma theme shows why that term
is so fitting.
"It has four layout settings. The Newspaper Layout puts widgets
into columns. Folder View displays folder contents with the user's
home folder as the default. The Desktop layout shows a more
traditional default view of panels and menus. The Search and Launch
layout adapts the search interface into a full screen
"You can also set wallpaper and position it six different ways.
Mouse actions are also configurable much more so than in earlier
KDE versions and in GNOME."