[cosmie]

> PS. the partner categories program has actually been discontinued as of April 2018, so these third parties will no longer be able to syndicate their data to all FB ads users in the future.

One thing to point out is that it's true that the Partner program itself has been discontinued, which gets rid of all the 3rd party targeting categories within the self-service interface using Facebook-managed data integrations with those firms.

But the ToS[1] rewrite effective 5/25/18 goes out of it's way to ensure that they don't outright prohibit the use of third party data. They just effectively decentralized the usage of it and require ad buyers and the data brokers to have a direct relationship now, and leverage the custom audience functionality you mentioned to do the targeting. And in so doing allowed themselves to become willfully blind to the usage of 3rd party data plus shifting liability onto the advertiser for usage of it.

[1] https://www.facebook.com/ads/manage/customaudiences/tos