[cosmie]

Facebook isn't targeting you, Amazon is. Amazon is targeting you on Facebook for things you just browsed on Amazon's app.

If you're logged in during your browsing, Amazon knows who you are. If you're not logged in, they presumably have enough heuristics to estimate who you are (based on previous logins from the device).

I don't know about their current programmatic bidding capabilities, but even on their Facebook's normal self-serve platform you can be targeted specifically by email (there's a minimum audience size for pseudo-anonymity purposes, but it's only like ~20 individuals).

Edit: You can go here[1] to see the list of advertisers that currently have you in their audience lists for ad targeting. Currently mine has Amazon.com, Amazon.co.uk, one of Netflix's new shows listed, and some weird political thing that isn't even for the state that I live in.

[1] https://www.facebook.com/ads/preferences/edit/

[mirkules]

Thanks for that link. It says Amazon has my contact info, but I'm not sure what they could have that ties my Amazon identity to my Facebook identity. I use a different email, different name, no phone number, no address on FB... I don't get it. It would be good if FB said what info they have.

[cosmie]

I agree that it'd be nice to know which data point was used for audience building.

   > I use a different email, different name, no phone number, no address on FB... I don't get it.

Not sure if phone number can be used for audience targeting (it's not available to self-service, normal advertisers iirc). But wanted to clarify this part. Just because you haven't added it in no way means that Facebook doesn't have your phone number. Or your alternate name. Or your different email address. With the way that the Facebook app syncs to most people's phones, all it'd take is one person associating your Facebook account with their phone contact of you for Facebook to start associating those alternative contact/data points with your Facebook profile.

[mirkules]

Interesting. Now that I think of it, for the last few months FB has been relentlessly trying to get me to associate my phone number with my account - and they even display it in Firefox (which was surprising that a browser could pull a phone number). After what you said, I wouldn't be surprised if they associated it anyway.