Amazon profusely apologized for the invasion of privacy, and provided the following explanation:
Echo woke up due to a word in background conversation sounding like "Alexa." Then, the subsequent conversation was heard as a "send message" request. At which point, Alexa said out loud "To whom?" At which point, the background conversation was interpreted as a name in the customers contact list. Alexa then asked out loud, "[contact name], right?" Alexa then interpreted background conversation as "right." As unlikely as this string of events is, we are evaluating options to make this case even less likely.
With that in mind, it leaves us wondering what exactly Alexa is hearing on a daily basis, and what commands it interprets. Luckily for us, Amazon provides this ability right from within the Amazon Alexa app, and it's very easy to access. This functionality has always been available to browse, but it's of course once again gaining prominence (for obvious reasons).
Accessing your Alexa voice command history is as simple as pulling up the Amazon Alexa app on your iOS or Android device.
From there, you will need to click on the hamburger menu in the top left-hand side of the app. Next, scroll down to Settings. From this menu, you will scroll down some more until you come across History under "Alexa Account".
Next, you will see your entire history of interactions with Amazon Alexa from all of your registered devices (in my case, I have one Echo Dot upstairs, and one downstairs). I primarily use my Echo Dots to control various smart devices throughout the home (light switches, ceiling fans, Nest Thermostats, etc.). So, it should come as no surprise that you'll see voice commands directed at these devices.
In addition to the text representation of all of your voice commands, there is also an accompanying voice snippet with each entry. If you don't like to listen the sound of your own voice, you might not want to go that route.
If you see "text not available", that means that Alexa heard its name called, but had no idea what the heck you were trying to say (perhaps in your late night drunken stupor). In this case, you can simply click on the audio recording to listen to what Alexa heard.
Amazon of course keeps these recordings to help tailor the user experience for your household, but if you're uncomfortable with these entries, you can delete them individually from the app. If you want to perform a wholesale wipe of recorded data, you'll have to head to "Manage Your Content and Devices" section of your Amazon account.