We see the periodic question in Blogger Help Forum: How Do I?.
How do I find out how many actual people are viewing my blog?Stats does not provide unique visitor counts - Stats provides pageview counts.
It's simply not possible to determine, with 100% certainty, how many different people are viewing your blog.
Consider these environments, where multiple locations, or people, are involved.
- A single person can use multiple computers, simultaneously.
- A single person can use a mobile computer, moving from one cellular connection to another.
- Multiple people can view the same computer, simultaneously.
- Multiple people can share the same computer, serially.
- Multiple people can share the same Internet connection, serially.
There are other visitor meters besides Stats - and some other such products will provide "unique" visitor counts. Each product, which claims to provide "unique" visitor counts, will do so based upon specific limitations and techniques.
One of the most obvious ways to determine unique visitors is by comparing IP addresses. Surely, two pageviews from the same IP address will be one person - and two pageviews from two different IP addresses will be two people, right? Wrong.
- One person can use two computers, simultaneously.
- One person can use a mobile computer, moving between two locations (each location will have a different IP address).
- Two people can use the same computer, at a library or Internet cafe.
- Two people can use the same mobile Internet connection.
It's even possible that two people can access the same page, from the same computer, one after the other. If the first person does not properly clear the computer, after use, the second page access will be from cache - and will not access the server. The second person, using that computer, will not show up in a Stats log. Again, two people can look like one.
Some visitor logs will drop cookies onto a computer. Detecting a cookie already in place, this indicates one person, returning - and successfully dropping a cookie, indicates a different person, right? Wrong, again.
- Again, a shared computer is a possibility.
- Not all computer owners will permit unknown websites to drop cookies, onto their computers.
- And some owners, when they permit cookies on their computers, will periodically clear cookies.
Some very sophisticated visitor logs can compare demographic details, similar to the Stats Audience display. Besides IP address, what can be determined?
- Operating system, brand, model, and version.
- Browser brand, model, and version.
- Maybe, location (possibly determined by IP address, again).
And finally, some visitor logs will compare IP address, over a given time interval. Arbitrarily deciding that all activity from the same IP address, over a period of 30 minutes, represents a statistical "single person", is a known technique. This is not a legally significant technique, however.
The bottom line is, as I state repeatedly, you simply cannot compare numbers from any two visitor logs or meters, with any degree of usefulness. Each product will have its own way of determining unique visitors - when they even suggest a "unique" visitor count. Stats simply avoids the uncertainty, and only provides pageview counts.