One of my few remaining complaints with my Google Home is that it responds to questions at whatever the current volume is. If I was listening to loud music earlier in the day and forgot to turn down the volume later, my request to turn off the room lights results in "OKAY, TURNING OFF THE BEDROOM LIGHTS" being blasted. This is no longer a problem for Alexa owners at least, with the new 'Whisper Mode' feature.
Once you turn it on, you can whisper a command to an Alexa speaker and it will respond at the same low volume. It's a bit creepy, but it's definitely something I wish my Google Home had.
The feature is rolling out now to all Alexa speakers. To turn it on, just say "Alexa, turn on whisper mode." You can also enable it from the Alexa app on your phone (Settings > Alexa Account > Alexa Voice Responses > Whispered Responses).