Based on the kind of things the Ad-tech industry does [1], without proper laws protecting users, I have absolutely zero...zilch trust in any advertisement company - I am not partial to Google, rope in Microsoft, Viacom, Amazon, Adobe, Oracle, all of them [2] (these are the top ad aggregators and auctioning houses).

The last company I am willing to give my health information is an advertisment company. Nothing to worry, the fox is doing a great job at keeping the hens safe.

[1] https://www.nytimes.com/2018/01/31/technology/internet-adver...

[2] https://en.wikipedia.org/wiki/List_of_advertising_technology...