How Piwik PRO recognizes returning visitors?
To detect if the visitor is returning, Piwik PRO will check the following:
first visit time
last visit time
This information is held in a tracking cookie and sent to Tracking API as
Additionally, on websites where the ecommerce module is working, Piwik PRO uses the
_ects parameter to recognize a returning visitor. When a visitor previously visited the website and ordered something, the time of the purchase is stored in a cookie. Anytime he or she visits the website again, the ppms.js tracker sends the
_ects parameter with that time.