User tracking - unique visitor length?



I was trying to determine when a unique visitor was calculated and came across this faq answer:

However, it doesn’t explain to me how long is this unique visitor counted as unique. I looked at the global.ini.php file and noticed a tracking cookie time expiration:

; by default, the Piwik tracking cookie expires in 2 years
cookie_expire = 63072000

Does this mean a unique visitor is considered the same visitor if they come back to the site within 2 years?

So basically, to my understanding it works like this:

  1. Brand new visitor comes to the site.
  2. Sets a cookie. If a cookie cannot be set, base it on factors such as IP, resolution, browser, plugins, OS, etc. to determine if it is the same user or a new one.
  3. If, unless cookies are cleared, this user come back anytime within 2 years, they are considered a returning visitor.



(Matthieu Aubry) #3

The metric “Unique visitors” is only for the selected day, per week or per month, not more.

If users keep the cookie then the visitor will have the same ID and also will be properly counted in “Days since last visit” , “Number of visits”, etc.