With the revolve (or “lathe” in some programs) tool you can extrude along a central axis creating the profile for many things. Lamps, missiles, machines, joints and a multitude of other basic objects can be built using this powerful tool. Think revolving a curve as extruding around a center point. If you haven’t watched the extrusion tutorial go here and watch it to get a basic understanding of how extrusion works.
Remember– the control line that you use to define your forms profile will be proportionately larger or smaller in diameter depending on how close to the pivot axis you place it.