Do you use google voice commands on your phone? If so, you might find this interest or scary.
Voice & Audio Activity is a feature of Google History that Google users can access to list and listen to voice recordings that they have sent to Google.
While I'm not actively trying to convince others that privacy is important and should not be neglected, it is often difficult to convince others when the topic is discussed.
One of the better ways in my opinion is to point users at services on the Internet that display usage data they have collected about users. Source
