[zerocrates]

I'm not extremely familiar with the ad industry, but isn't this setup (tell us who you want to target and we'll do it for you) the way that the other big platform holders work, like Google and Facebook? That's always been my impression, that the data is their "secret sauce" and they aren't interested in sharing.

[lozenge]

You can upload email addresses and phone numbers to Facebook to target and you can set cookies on your website for retargeting too.

[ENGNR]

I imagine that's only because FB/Google want to protect their distribution, and users run ads directly with them. Smaller publishers have no choice but to give it all up to the ad networks