I'm not sure anything is 'clear' in the situation. He could have had some implementation of some kind of basic messaging functionality, which for any number of

I'm not sure anything is 'clear' in the situation. He could have had some implementation of some kind of basic messaging functionality, which for any number of reasons they may have decided to implement themselves, which is pretty rational for a whole host of reasons. If an employee is trying to sell a 'side project' to a Corp. they are acting effectively as a 3rd party and should expect to be treated as such. If there was some material, core IP that was infringed upon, maybe there's an issue, but otherwise some kind of independent implementation is probably within bounds. I can't speak to what extent there was 'carbon copy' of features, or even if that is lawful or what not. Think of it like this: company ABC pitches their app to Airline. Airline decides to roll their own, and the feature base seems quite similar. That's pretty normal.