The Conversion Tracker
When a customer clicks on a link in a Connect message, cookies are set in the customer’s browser:
kc_customer: Contains the customer_id with has a long expiration date (set as a system parameter)
kc_click: Contains the full click context (i.e. customer_id, instance_id, event_queue_id, and link_id). This cookie has an expiration (1-2 days also set as a system parameter). The cookie name includes the instance ID (e.g. kc_click_127). As a result, there is one cookie for the last click of each link instance.
HTML and Read detectors: These pseudo-clicks only set the kc_customer cookies
When the conversion tracker recognizes a click-through as a conversion, it bypasses the normal click-through handling code. It creates a ConversionLogEntry (logger package) containing the click-through context retrieved from the cookie and the unparsed query string from the conversion detector.
If the conversion tracker receives multiple link cookies they are stored in the log entry. The profiler selects the appropriate cookie.
Duplicates
After receiving a conversion, the conversion tracker sets a third cookie, kc_confirm (with a short timeout system parameter configuration). If this cookie is present when the conversion is received, the conversion tracker assumes the conversion is a duplicate and discards it. The value for this cookie is the date the last conversion was received.
System Parameters
The conversion tracker uses the following parameters:
TR.UseCookie (Category: Network, Access Level: Advanced Access): If set to "FALSE", the conversion tracker will never set cookies
Timeouts: Each of the three cookies have a timeout parameter:
kc_customer: Extended timeout parameter
kc_click: Timeout parameter of 1 to 2 days
kc_confirm: 30 minute timeout parameter
No cookies are included: Cookies can be blocked, expired or never set (using a system parameter). If the conversion detector data includes the email address, then a log entry is created. Otherwise, the conversion is discarded.
Some Cookies Included: If some cookies are present but not others, the log entry contains the data present
kc_confirm: If kc_confirm is present the conversion is discarded as a duplicate
For additional rules, please see The Profiler.