It allows you to create a face from a single vertex selection or a single edge selection, while retaining all the built-in functionality. Simply enable the add-on, and pressing the F-key will be better than ever before
F2 Modeling Addon for Blender (also known as the spider-script) can create quad faces from vertices, or from edges, and provides direction control for creating faces, drastically speeding up the modeling workflow in Blender to a more fluid and intuitive method. F2 is provided as donation ware, and there is a support thread for this script at BlenderArtists. Check out the F2 Modeling Addon for blender here.