What Is The Difference Between First Click Conversion Tracking And Last Click Conversion Tracking?

First Click Conversion tracks any conversions that resulted along the conversion path based on the first interaction of the link click. For example, Sally sees an ad and clicks on it to the product landing page. She leaves the page and after a few hours, she visits the site again and makes a purchase. The purchase is a result of the first interaction of the link click from the ad to the product page. 

The Last Click Conversion is attributed to the conversion that resulted immediately after a link click. For example, Sally sees an ad and clicks on it to the product landing page. She leaves the site and continues to browse the internet. Sally sees a retargeting ad as she browses on other websites. She clicks on the ad and makes a purchase. The purchase is a result of the last interaction of the link click from the retargeting ad to the sale.