Pleisty is tracking website users based on Anonymous User IDs (AUIDs) stored in cookies.
In order to link the anonymous user id to a real user (identified by email / CRM user ID), it is required to receive, once per AUID's lifetime, information about the user's identity. This can be achieved in two ways:
It is possible to simulate a login for a user coming to your site from an external system by adding the pleisty_u paramerer to the URL: http://example.com?pleisty_u=CUSTOMER_ID
If you use the email address as CUSTOMER_ID, the URL will look like this: http://firstname.lastname@example.org
As a best practice, add this url parameter to all newsletter links sent from external systems (ex: logo link, footer links, other links), so your users will be properly identified when they land on your shop.