Depends on the degree of certainty I suppose. If it's close to 1 then probably not much though it does potentially provide more data to cross reference against when linking activity across services.
Techniques such as using different email addresses and other first party data would no longer be effective for limiting cross linking of user data (fingerprinting is an issue as well) if a legal ID is required and that data is shared with the service.
I’m on the fence about a service only using ID verification even from a fully trustworthy third party and not gaining any additional info (save for maybe a random unlinkable ID to prevent multiple accounts or perhaps just a flag indicating whether the ID is eligible for an account on that service). Even that bothers me. I would have to think about it some more. But I kind of do get it and see how that could enable better online communities. I’d like to think there is a better way though.
Techniques such as using different email addresses and other first party data would no longer be effective for limiting cross linking of user data (fingerprinting is an issue as well) if a legal ID is required and that data is shared with the service.
I’m on the fence about a service only using ID verification even from a fully trustworthy third party and not gaining any additional info (save for maybe a random unlinkable ID to prevent multiple accounts or perhaps just a flag indicating whether the ID is eligible for an account on that service). Even that bothers me. I would have to think about it some more. But I kind of do get it and see how that could enable better online communities. I’d like to think there is a better way though.