- He worked on a personal project during company time. Edit: Oops. I misread this one as the inverse of what the author was saying. He only worked on it while employed. Still very ugly given the field of his work.
- His personal project is directly related to his work.
- His personal project conceivably competes with his employer's products.
- The company does not have staff in NY or CA, so the author lacks even the minimal limitations on non-competes imposed by state law (http://newappendto.wpengine.com/wp-content/uploads/2013/12/1...)
All of these things are typically barred by completely reasonable non-competes. As the author, I would absolutely expect to receive a C&D. As his former employer, I would feel (personally) hurt, even betrayed, by this behavior.