What did Edward Snowden do when working for the NSA and why were his actions so controversial?

What did Edward Snowden do when working for the NSA and why were his actions so controversial?
Is Edward Snowden a whistleblower?
Was Roger Boisjoly (see chapter 2) a whistleblower?
Propose, by using your own words, a precise definition of whistleblowing.
Apply Daviss complicityavoiding theory of whistleblowing to the Edward Snowden case. Was Davis obliged to blow the
whistle according to DeGeorges theory?
To what extent, if any, do the theories proposed by DeGeorge and Davis appeal to Kantian and utilitarian moral considerations or
intuitions?