It remains unclear. There are reasons to believe they are (it'd really improve their ad targetting, and there are some anecdata to suggest they are), reasons t

It remains unclear. There are reasons to believe they are (it'd really improve their ad targetting, and there are some anecdata to suggest they are), reasons to believe they aren't (they must have some ethics, and if they got caught, the result would be Bad), and reasons to believe they can't (constant audio recording would cause a suspicious drain on battery).