In Metacity, I can move a window normally, and it snaps against edges when it comes within a distance of N pixels of that edge.  This is very similar to Openbox, which has resistance instead of snapping.

This feature request is about what happens when you hold down the Shift key while dragging a window in Metacity.  Then, the window is always snapped, and it becomes impossible to move a window anywhere else except the snapped positions.

For example, if there is only one window on screen, then there are only four positions this window can be moved to: the four corners.  It suffices to position the mouse pointer in a quadrant of the screen in order to move the window into that corner.