So a couple of days ago my manager pointed out something peculiar on our statistics that we accumulate for everyone that visits our sites. Our stats are very granular, and one unique thing is that we have a dynamic 3rd level domain. The stats pull and group the data based on these “Virtual Domains” and then output the number of unique visitors as well other stats like page views.

The peculiar part was that for our number of visitors for a particular Virtual Domain we had 24,000 unique visitors, however we only had 20,000 page views. That is odd, how can a person visit the site and essentially be recorded as a unique visitor but never show as a page view?.

Here is the answer. Other sites that link to your images as well as emails that link to images or videos will show as a unique visitor because the computer has to grab that image from the site which shows a hit as a unique visitor, but it does not have to open a web page to grab that image. Therefore it is possible for this to happen. It can also happen when a user has multiple IP’s assigned to their pc… however this is more uncommon than the first scenario.