How Many People on a Computer

We are not yet living in the era of one person, one computer.

Once you've removed the robots from your reports, you now have to sift through and determine how many people are represented by all those clicks. By lumping all of the requests made from the same computer (207.154.137.4, for example), you can assume they all came from the same person. Except for two things: dynamic assignment of IP addresses and gateways.

When you dial into your local ISP, you are assigned an Internet Protocol (IP) address. That number is going to be drawn from a pool of numbers the ISP has on hand and you can be pretty sure you won't get the same number each time you dial up. Let's say you go to a certain site and then hang up your modem. Somebody else dials in, gets assigned the same IP address you were just using, and goes to the same site. The server logs for that site would think the two of you were one and the same.

The home computer is used by the whole family, so even if it does maintain the same IP address, your server log can't tell the difference between Mom, Dad, Wendy, or Doug. The office computer used to be for the use of one individual, but the issue became clouded with the advent of notebook computers and wireless networks. Here, the local area network is doling out those IP addresses as needed, just like the dial-up ISP. Turn your notebook off and the IP address is sucked back into the pool for the next wandering employee.

Another log-baffling situation comes as the result of gateway computers. These are the systems that protect internal corporate networks and control the large number of users on online services such as America Online. Everybody surfing via America Online comes through an AOL gateway to your site. That means ten different people can look like one. Is that somebody from Microsoft who seems to be very interested in your Web site? Or is it 200 people from Microsoft who were incorrectly told they could find a funny picture of Bill Gates on your site, found out there wasn't, and left? Due to the firewall hiding the final IP address, they all look like one person.