This is cool - but I feel like to do this well you need to co-mingle valid and masked emails on the same domain. Otherwise services can and will prevent folks f

This is cool - but I feel like to do this well you need to co-mingle valid and masked emails on the same domain. Otherwise services can and will prevent folks from signing up with @duck.com emails. Apple does this well with their email masking service; all emails have an @icloud.com domain, the same as primary emails. A service can't simply block @icloud.com without blocking millions of primary/default addresses.