How do you definte a Unique Visitor?

[moojj]

I have noticed that advertisers are very interested in in how many unique visitors your site receives. Unfortunately my current stats only show number of requests and number of page requests, no unique requests.

I'm going to create a little script to see how many unique hits I get every month. However, I was wondering what the definition of a unique hit is..

I did a bit of google searching (http://www.google.com.au/search?hl=en&lr=&c2coff=1&safe=off&defl=en&q=define:Unique+Visitor&sa=X&oi=glossary_definition&ct=title) but there seem to be several definitions.

So I will throw this one out to the PF community, what do you consider a unique visitor?

[Anthony]

I define a unique visitor as a person visiting your site from a unique IP address :)

[moojj]

I define a unique visitor as a person visiting your site from a unique IP address :)

I see a problem with this..

Many ISP's have transparent proxies these days, so one visitor on your site could use several different IP's. Additionally, several users from one ISP will be using the same set of IP's.

[Submerge]

I define a unique visitor as the first page request by a unique IP-address for a period of a month. This way is the easiest way, and only way I know of, to track unique visitors on the World Wide Web. unless there was a way to track the name, location, and any other identificational attributes of a person on the Internet. Since there isn't as of right now, you can only truely go off of IP-addresses.

More than one person can share an IP address, but I don't think the advertisers care and only want the count of unique IP addresses to keep visitor inflation from happening from shady webmasters.

[Tyler]

I believe the industry standard is a connection from a specific IP within a 24-hour timeframe. So, if Joe visits Example.com once a day for a month, is registers as 1 unique a day, totaling 30 uniques a month. If he visited 3 times a day, it still registers the same. If he visited twice per day, one from his computer upstairs and one from his computer downstairs, it would register as 2 per day, or 60 a month.

[Idle Play]

Spot on.

[kaizan]

Someone with two sets of genitals?

(ok that was off topic ;p)

[Gareth]

Spot on Tyler, and I just look in awstats :p