Jim Lindgren at Volokh tries to recapitulate Mr. Geithner's experience using Turbotax back when he was an IMF employee and failed to file properly (as self-employed). I think it's an example of the loss of expertise when we incorporate knowledge into our tools. I know when I filed my taxes on paper, I was much more aware of what I was doing than when I answer Turbotax's question. As I told my wife, it's sort of a mindless exercise now (which made her feel very good about the accuracy of our returns).
It's the same sort of thing I saw back when I worked for ASCS:
A district director took me around his district in North Carolina. He told me he tried to have his office managers (i.e., CED's) assign their best clerk to handling "reconstitutions" (i.e., the changing of farm records), because it was complex and important. Some 15-20 years later I found myself responsible for the people who were automating the process, trying (and perhaps failing) to make it simple and easy for any program assistant to handle.
Along the same lines, I remember an employee discussing the new word processor (one of the first with a CRT screen where you could actually insert and cut and paste and see the results of your action). She said it was nice, but she used to be proud of her ability to type fast with no mistakes. And now she was losing it, because the machine took away the premium on not making errors.
Just as, baling hay rendered obsolete the skill of making a good load of hay on the haywagon (i.e., defined as one where you got the maximum of hay on the wagon, placing your fork-fulls so that the hay bound together (i.e., being attentive to the direction the stalks of hay were lying on the wagon). And I suppose now the skill of stacking rectangular hay bales on the wagon or truck is obsolete, as you just use the forklift on the tractor to move the big round bales.