There's been a spat of privacy-based communications companies shutting down of their own volition rather than cooperate with governmental surveillance measures.
Two heavyweight names in the encrypted email space, Lavabit and Silent Mail, have taken themselves out of commission in what many consider an honorable act of "privacy seppuku." They did this because they preferred to go out of service rather than allow the government access to their system.
According to the company’s founder Dotcom, Mega doesn’t hold decryption keys to customer accounts and “never will”, thus making it impossible for it to read the emails. This also means that Mega by design cannot be forced to rat on its users by intelligence agencies.