Join Date: May 2007
Location: Fayetteville PA
Well....here goes.....as best as I can.
 The dado cuts for the back (¾" thick for me), top and bottom actually perform as a rabett cut in that when assembled, the back is flush with the edge of the sides as are the top and bottom.
 As to the screws going in from the outside, that is only when there is another cabinet or a dress panel going against it to conceal the screw heads.
 The angled brads go through the shelf at about 30 degrees and penetrate the side. The back can be nailed into the edge of the dado as can the top and bottom. The specific purpose of the brads is to hold everything together until the glue cures.
 Pocket screws are used in conjunction with pocket screw holes, pocket screw drill fixtures and pocket screw drivers and the current leader of the pack is "Kreg". Give them a look. Once you try them you will find a gozillion uses for them.