When you type so often that you begin to write out common typos that would occur when typing, such as switching a "t" for an "r" (because t and r are next to each other on the keyboard).
I was writing my essay by hand because my computer was broken when I wrote the word "proffesot" instead of professor. It was a classic example of my typer's writing syndrome.
by Chad Bueller February 3, 2009