from what I understand on step 4, you make a duplicate layer of your render layer and guassian blur it and set it to overlay or hardlight.
than you make another duplicated layer of your render and I guess move it under ur original render layer(I guess so you have an untouched render layer, you could just duplicate it and use the duplicated layer)
than motion blur it angle 0 im guessing and 70 and duplicate it a few times and move them around the sig to cover it.
than duplicate render layer
than you take the caligraphic brush and just start on the left and hold it while moving to the right, seems like what he did(well this doesn't work, so I have no idea what he did)
ill try this out guys and tell you if this is what he meant
arg wish he could redefine this tut