Screen space is a limited resource for computer users-multiple monitors are one means of workspace expansion, and "virtual desktops" are yet another way to increase screen real-estate. We present a taxonomy of organization strategies based on our observations during a series of interviews with virtual desktop users. Additionally, we explore causes of varying user preferences for physical versus virtual means of screen-space expansion. Finally, we discuss the design implications of our findings. Keywords Virtual desktops, multiple monitors, information organization.