There is MUCH more to knife sharpening than just getting a sharp edge. There are matters of edge geometry, what finish allows for food to not stick to the surface of the knife, and many other things. I feel that if I asked Harrelson what stone I should use for task x or task y, he would invariably respond that I need a shapton... but there are some things that shaptons do NOT excel at. Shapton stones leave a very bright polish, which is not good for some situations. For example, consider this photo:
http://img.photobucket.com/albums/v4.../JKS/After.jpg
See the wavy line at the edge? A shapton would make that whole bevel a shiny mirror, whereas the matte surface higher up the bevel allows for better food release. Try a King 800 or 1200 on something like this, then try a shapton. Big difference. I know Dave Martell knows these things inside and out, and so I turn to him for my knife sharpening knowledge.
I've never seen Harrelsons knife sharpening video, so i can't comment there, I guess.
As far as Jointing vs Joining, there is a difference.
As you have a picture of a nice japanese chisel as your avatar, I'm sure you've tried your hand at a dovetail joint. Or a half-lap, mortise and tenon, butt, finger, rabbet, or any other number of joints. Joinery, or joining, is the fitting together of two or more pieces of wood or some other material by way of these joints.
A picture of nice joinery:
http://finewoodworking.taunton.com/a...tos_001_lg.jpg
Jointing, on the other hand, is the flattening and truing of a board. For example, think of an edge grain cutting board (not butcherblock). Here's a pic:
http://www.vermontbutcherblock.com/c...alnut%20cb.jpg
This board is made up of alternating pieces of maple (the lighter wood) and walnut. each piece of maple and walnut has to have a very straight and flat face to glue up well with the next piece.
Making the pieces square, straight, and true is jointing. Connecting the pieces together with glue and pressure is joining. (Not all joinery needs glue and pressure, however.)