Facebook's not helping this conspiracy theory with their "why did I see this ad?" dialog. I'll see a clearly hyper-targeted ad (for example, a psoriasis medication) and click that button and it'll say "they wanted to reach people in the United States between 18-65!"

I know I was targeted by that ad. I know they're just showing me the most general bit of the targeting info that was used to put that ad in front of me.

The dialog even obnoxiously says "There could also be more factors not listed here." Yes, I know, that's fairly obvious. I clicked the dialog to figure out what those were.

>I know I was targeted by that ad. I know they're just showing me the most general bit of the targeting info that was used to put that ad in front of me.

How do you know this? I get ads for male pattern baldness all the time but I'm not even genetically at risk. Half my ads on hulu are for tampons, and no woman lives in my house. Ads really aren't that good. Facebook might've just gotten lucky...

> How do you know this?

Because if I head to https://www.facebook.com/ads/preferences/, they have a wide variety of bits of info on me that permit this exact sort of targeting, and it'd be really dumb of them not to use them.

If I head to Facebook's ads manager and create a custom audience, typing "psoriasis" in the box gets me "psoriasis awareness", which consists of 19,402,670 "People who have expressed an interest in or like Pages related to Psoriasis Awareness". Chances are good I'm one of them.

Visited webMD or a medical site for it? They have a FB Pixel on there, so you're in that audience.

Visited /r/gaming or kotaku? You'll get an ad for a switch.

Yep. Plus, data brokers like Experian provide a linkage between me and things like my credit card purchases.

Plenty for Facebook to have creepily accurate targeting without needing a microphone listening in.

Just because that's an option doesn't mean that the ad you saw used it. Advertisers might get a better rate with a wider net; everyone in that audience has done at least a little bit of research, and might be less willing to switch than a random male would be to start using any medication at all.

I am a professional FB advertiser.

The advertisers are probably choosing to target everyone on FB in that age range, but asking FB to optimize for conversions. Then the FB algorithm finds more people who look like people who are clicking and converting.

Ok, so dumb question. Why _wouldn't_ you optimize for conversions then? Unless you want some immeasurable branding value type lift.

Sorry for the dumb question but if you're implying one particular bidding mechanism benefits from FB algorithmic experience in a way that's meaningfully more accurate (serving the ad to the guy or girl with the condition), why would anyone do anything different?

Almost everyone who cares about performance does bid for conversions. Sometimes companies add extra layers of targeting on top of it though.

Because they are idiots.

Non conversion optimised ads can work for small audiences of really high value, but that's a pretty niche use-case.

That feels a bit like money laundering for targeting parameters.

18-65 _would_ get them to a 5% hit rate and few false negatives

Is there any evidence to suggest those rumors are actually the result of unusually high levels of sophistication on the part of Facebook's ad targeting systems, and not just an artifact of confirmation bias and the Baader-Meinhof phenomenon?

Not really, the truth is likely much more mundane: People are fairly predictable [1] and their predilections aren't that unique [2].

1: https://www.forbes.com/sites/kashmirhill/2012/02/16/how-targ...

2: Real conversation I overheard: "I was talking to my friend about buying a switch and the very next day I got FB ads for it!" - well duh, it's the holiday season and game consoles are very popular gifts.

Why would it need to be unusually sophisticated?

Speech to text and keyword search are both fairly mundane.

People also think God made the earth in 6 days. What mass groups of people believe isn't indicative of Jack.