All smartphones now come with programmable low-power audio recognition DSPs for always-on "Hey Siri" and "Ok Google".
So it's here.
So it's here.
I'd even try it myself, but I don't have a facebook account, or any devices with "personal assistant" apps for that matter. For the obvious reasons.
The FTC just made an announcement about SilverPush, an example of such software:
https://www.ftc.gov/news-events/press-releases/2016/03/ftc-i...