3 ms·

They don't. It's frequently been alleged, but is not true. https://www.vox.com/the-goods/2018/12/28/18158968/facebook-microphone-tapping-recording-instagram-ads

• sneak 6y ago
  From that article, after a bunch of paragraphs about how Facebook probably isn't listening to your speech (but also isn't trustworthy): > Another report, published in Wired last year, explained how hundreds of apps use “ultrasonic tones” to track where you’re going in physical space. These apps need access to your microphone, but not to actually listen to you, just to “beacon” noises emitted in stores and by advertisements. So ... rest easy.