Quick Shopping Cart's conversion tracking measures the action of a user who clicks on one of your ads and whether the action results in a purchase.
You can set up conversion tracking to track the effectiveness of your Google® AdWords®. When your customer completes a Quick Shopping Cart purchase, a message is sent to the advertiser's conversion tracking server, where you can see conversion statistics.
When generating your Google® conversion ID, select Purchase/Sale in the Google® AdWords Conversion Tracking setup. Additionally, even though the Google® instructions tell you to copy all of the code in the box, you only need to copy the ID in the google_conversion_id line. You use the ID to set up conversion tracking with Google®.
For more information, see Google's Setting up Conversion Tracking section.