sponsors and billers passing through unique tracking ID
 

If sponsors and 3rd party billing companies had an extra field that we can supply, which shows up in our sales stats, then we could track the 'specks of gold' that have purchased memberships as they pass through our site again.

ifriends/clickcash have the "ART=" parameter in their linking code, which is just an arbitrary string that is also listed in the stats. This is intended to be used to show which banners perform best, but it could also be used to track the unique ID of visitor who has a credit card.

Thoughts...?