How do you define a "Unique" visitor?

[Simmo!]

I've noticed that most stats programs, counters etc define "Unique visitors" based on a different time period. Someare happy to log a Unique every time someone leaves a site and returns regardless of time period, others like StatCounter let you set your own time period for definition while counters like Quantcast work over an undefined period effectively counting unique "eyeballs" based on repeat visits from an IP.

The latter obviously will show far less uniques than a definition of 24 hours which in turn will show less than 1 hour which in turn show less than counting on a simple return to a website. In cases like StatCounter, if you set "1 hour" for example and someone is still on your site over an hour later, their visit counts as 2 visits.

So I am interested in how you would define a time period for a "unique". Say you were looking to buy a site, what would you consider a reliable time period to report on unique visitors?

[RayUK]

I put 'over a month' mainly because that is how AWstats calculates it and that is what I use on my site to track my own traffic. I do think that a month is probably a bit long, but on the other hand just 24 hours is probably a bit short.

I don't really know what a good time would be!

[Simmo!]

I use 24 hours as a marker because I think if someone comes back again after that, it is a conscious (or event-driven) decision. As a result of that method of thinking, if I was buying a site I'd consider this a fair reflection of uniques measurement I guess.

[RayUK]

That is an interesting point, you are valuing repeat visitors as more important than unique ones (and I agree). But, by definition, if it is the same person coming back they aren't unique!

More a comment on uniques not being the be-all and end-all of traffic really If I had a site that sold expensive widgets I would rather have 100 repeat visitors that dropped a few grand a week, than 100,000 unique visitors that weren't interested in expensive widgets.

[Nandakishore]

According to my understanding when a visitor is counted only once in 24 hours irrespective of the number of his visits to that site on that day, it is counted as a unique visit. However, I am not very sure whether this is counted for the entire domain or for each entry page.

[baldidiot]

I put 'over a month' mainly because that is how AWstats calculates it and that is what I use on my site to track my own traffic. I do think that a month is probably a bit long, but on the other hand just 24 hours is probably a bit short.

I don't really know what a good time would be!

+1

I take my data from awstats too. I assume that it counts it once per reporting period (calender month).

[best.hands]

I would agree RayUK. Unique visits can be best identified in a monthly period. Within the period, any recurring visits coming from the same IP should be considered page views and adds up to site's visitors loyalty.