This came up through an ex-user who complained that their account name was still visible on a remote pod. It turned out that everything had done properly, but their ID contains their real name.
Would it not be a good idea to replace the user_name part of the ID with something anonymous? It could be replaced with
[closed account], possibly with the pod name appended, e.g.
There is, I assume, no need to retain any account-level information relating to a closed account in a post on which that account has commented, as there is nothing to link to (clicking on the account name gives a flag that the account has been closed). So why not just erase the account name so that it can’t be clicked on? And the guid/public key for that account can be deleted from the post and the pods holding the post, as there probably can’t be any need to refer back to the now closed account.
I don’t see this as a legal (e.g. GDPR) issue. If someone wants to be forgotten, they can go to the My activity stream and remove their interactions before closing their account. But unless there’s some good reason not to anonymise any remaining interactions after an account is closed, I think it would be a good idea to do so.