When it came to 3D modeling it used to be that once a 3D solid was created, if it needed to be changed, it was almost faster to just create the object over again… then “The Presspull” tool came along and it was one of the best functions to be introduced (a few years back), and allowed you to easily to create 3D shapes from 2D boundaries and closed loops or to quickly modify the face of an existing 3D solids.
But it had some limitations so often the user would have to do some other modifications to the solid even after the extrusion. Autodesk developers realized this and have once more jumped in to make your like easier. Now the Presspull tool (available on the Modeling panel of the Home ribbon tab), is enhanced in AutoCAD 2013 to be more flexible and context-sensitive. It now has a new Multiple option (or simply use the Shift key) to press or pull multiple objects in a single operation, and they do not have to be extruding in the same axis. You could be simultaneously extruding (positive or negatively) one or more faces say in the X-direction while extruding others in a different direction.
Additionally, you are no longer limited to clicking inside a bounded area. Now you can select 2D and 3D curves that are open or closed loops as well, as long as the curve is not self-intersecting.
Here is a chart that will help explain the behavior for different types of objects selected.
Lastly, now when selecting a face with the Presspull tool, the default behavior extrudes the face straight out. If you press the Ctrl key when you select a planar face, you can offset it as it extrudes to follow the taper angles of adjacent faces.