> If you don’t turn it on, we won’t use your microphone to try and match TV or music when you write a status update. If you do choose to turn it on and later decide it’s not for you, you can easily turn it off at any time.
> Fact: Nope, no matter how interesting your conversation, this feature does not store sound or recordings. Facebook isn’t listening to or storing your conversations.
> Here’s how it works: if you choose to turn the feature on, when you write a status update, the app converts any sound into an audio fingerprint on your phone. This fingerprint is sent to our servers to try and match it against our database of audio and TV fingerprints. By design, we do not store fingerprints from your device for any amount of time. And in any event, the fingerprints can’t be reversed into the original audio because they don’t contain enough information.
The app does fingerprint the audio and send it to their server to match a movie or audio. But they say they don't save it.
[1]: http://newsroom.fb.com/news/2014/05/a-new-optional-way-to-sh...