In the bright-eyed naiveté of my first few weeks as Facebook's first leader of the ads targeting effort, I'd eagerly confront each new conspiracy theory.

"Is Facebook scanning my photos and using that for ad targeting?" was one from a Los Angeles Times reporter. "My cousin uploaded a photo of her boyfriend in a San Francisco 49ers jersey, and now I'm seeing 49ers ads. How'd that happen?"

And so it went.

I'd also field new targeting ideas from Facebook employees themselves, who would construct just-so stories around some niche piece of user behavior, and how that could move the needle on Facebook's already soaring ad revenue (e.g. 'show burger ads to people who checked into In-N-Out').

Inevitably, the conspiracy theories and new ideas would die on the rocks of the threefold criterion I eventually formulated to debunk or discard (almost) all of them.

Is it possible?

Is it common?

Does it work?

WIRED OPINION ABOUT Antonio García Martínez (@antoniogm) was the first ads targeting product manager on the Facebook Ads team, and author of the memoir Chaos Monkeys: Obscene Fortune and Random Failure in Silicon Valley. He wrote about the internet in Cuba in WIRED’s July issue.

Feasibility, ubiquity, and efficacy: Those filters demolish almost every Facebook conspiracy theory you'll ever hear.

One that you may have heard recently: Facebook snoops on you via your smartphone's microphone. As with all such theories—9/11 truthers, Obama birthers, 'grassy knoll' advocates—there's just enough seeming evidence to wrap a story around. Here's one viral video supposedly demonstrating the phenomenon.

But it's all bullshit.

Let's put our corporate-branded Facebook product-manager hoodie on for a closer examination. Even if you haven't deleted the Facebook app from your phone, or relegated your phone to a soundproof box, a quick walkthrough of this most recent theorizing will demonstrate just how Facebook thinks about monetizing you, and why your microphone doesn't factor in.

Is It Possible?

To make it happen, Facebook would need to record everything your phone hears while it's on. This is functionally equivalent to an always-on phone call from you to Facebook. Your average voice-over-internet call takes something like 24kbps one way, which amounts to about 3 kBs of data per second. Assume you've got your phone on half the day, that's about 130 MBs per day, per user. There are around 150 million daily active users in the US, so that's about 20 petabytes per day, just in the US.

To put that in perspective, Facebook's entire data storage is 'only' about 300 petabytes, with a daily ingestion rate of about 600 terabytes. Put another way, constant audio surveillance would produce about 33 times more data daily than Facebook currently consumes.

Furthermore, such snooping would be eminently detectable, ringing up noticeable amounts of data on your smartphone as Facebook maintained your always-on call to Zuckerberg. Ever searched for something on your phone while making a call? Notice how it slows to a crawl? Your phone would be like that all the time if Facebook were listening.

Of course, there's a smarter way to do it. The Amazon Echo voice-controlled personal assistant (and its Google equivalent, Google Home), put a slightly Orwellian-seeming listening device in many American homes. The Echo has just enough hardware to detect a very small set of 'trigger' words, which start it listening. Once it detects that trigger word, it's also just smart enough to record the command that follows it, and send it to the Amazon mothership, where the real speech-to-text translation and natural language processing work happens. Data or a request for more details are then beamed back, and your conversation with 'Alexa' continues. The Echo functions merely as a microphone, speaker, and weak computer that does a small voice-recognition task well.