FB also has shadow profiles of people whom they track even if they're not signed into the FB or even have a FB account. How do you suggest I opt out of that?

https://theconversation.com/shadow-profiles-facebook-knows-a...

Good question. Probably you need to send a data request, so they can provide you with info they have about you. But based on what should they search in their data warehouse? IP? Cookies? Interests? Leaked email?

I guess one way to avoid shadow profiles would be to block FB scripts/cookies on pages you visit, so they won't track you.

Does deletion of your data unlearn the models from the data?

I don't really know this. Just provided what similar functionality exists in FB.

It's a black box for most of us. You might need to provide fake data to make it relearn. There were comments here and there about people liking various pages/posts not related to them, just to feed it with junk.

it was probably rhetorical, lol

I don't even think it guarantees that new neural nets won't be trained on your 'deleted' data

Of course not. What would that even mean? Their objective is to model you. To maximize profit, they should retrain the model with the input "user deleted this and that". As added data points.

Perhaps, that would mean complying with GDPR? You are obliged to remove data physically from databases upon request (including backups if possible, if not possible then keep deletion patches to be ran after backup restore!). Since you cannot continue processing data after GDPR deletion request, that could mean that a model (which is processing the data) should unlearn any knowledge of you.

This is what any reasonable person will think. I fully expect FB to argue that "oh these are just some computer bits you see. There is no way to from this model deduce what inputs made it into this model. It's like a hash function. And since we have removed the inputs, we have complied."

That they are in essence keeping "the ghost" of a person is another thing.

I don't even know if deleting your account through standard Facebook means is the same as requesting the deletion by GDPR request.

Delete merely updates a flag to deleted=true so it doesn’t show in the interface.