[mmmm]

Do they send sound from your phone to their servers non stop? If so, I'm switching from iPhone straight away.

[budu3]

The Moto X has a "Google Now" functionality where the continuously listens for you commands. Whatever is ships your sound off the Google server is another question.

[SlashmanX]

That's not how that works. There's something on the chip to just detect keywords, it's not a "always listening" thing