ClickBank HELP!
The cbf session identification parameter allows you to offer PitchPlus Upsells to customers with disabled browser cookies (approximately 10% of customers). You are not required to use the cbf session identification parameter; however, if it is not used, customers with disabled cookies will be redirected to the standard order confirmation page, rather than your first PitchPlus Upsell Pitch Page.
When the customer makes a purchase, ClickBank will pass the cbf parameter to your first PitchPlus Upsell Pitch Page. You must then capture the parameter and pass it back to ClickBank in the payment link. This may be accomplished using a dynamic programming language such as Perl, PHP, JSP, ASP .Net or others.
An example of how to retrieve the parameter using PHP is:
$_REQUEST['cbf']
Example payment links:
http://3.somenick.pay.clickbank.net/?cbur=a&cbf=<parameter passed>
http://3.somenick.pay.clickbank.net/?cbur=d&cbf=<parameter passed>
SOURCE: https://support.clickbank.com/entrie...itchPlus-Flows