Google records and saves snippets of what you say to "help Google understand what you say when using features like voice search". The sneaky buggers!
You can easily see if Google is mining away your smooth tones here: https://history.google.com/history/audio.
Some of you may have turned this function off and will not find anything, but if not - like me you will have a number of clips saved that you had no knowledge of. I have found 18 clips on my account, each clip is date and time stamped including the application the clip was recorded in. My recordings ranged from conversations about my mother to me boasting about the disco music at NYE!
You can delete these, if you like, by selecting each entry to the left and then hitting delete at the top right. I'm keeping mine, I like seeing what Google finds interesting.
If you found anything interesting let us know!