That is not really relevant because if a user comes from a different website and the referrer is not present, it will be counted as unique. Having a referrer of

That is not really relevant because if a user comes from a different website and the referrer is not present, it will be counted as unique. Having a referrer of that other website or having no referrer does not change anything. We both treat them as unique. The only referrer we actually use is the one from the same site to the same site. Those requests are always with the same protocol (and if you not you should change that). In that case we see both the hostname and the referrer are equal thus being non unique.