I'm trying to create a custom made class that will track the hits, unique visitors, IPs of visitors, referrers, and the landing page. I'm mostly utilizing the $_SERVER global however in the last two hours I've gotten 112 hits and 41 unique visitors. This part is correct, however, I see that some people don't have a referrer and a their landing page is nested deep or a blog article. You can check my statistics below:
I'm wondering how people can land on a blog article or service page without having a referrer. There's no way they can have it bookmarked so what's the other reason?