And even if it were trivially easy to pull off surreptitious microphone monitoring, Facebook's incentives to do so aren't obvious. You can't charge advertisers

And even if it were trivially easy to pull off surreptitious microphone monitoring, Facebook's incentives to do so aren't obvious. You can't charge advertisers more for an ad-targeting feature which officially doesn't exist (and if optimising targeting above and beyond expectations was that important, they could probably start by fixing some of the terrible choices made by self service buyers that wouldn't incur the same risk)