I have an ecommerce website using Paypal Account Optional, which doesn't always send the customer back to my site after payment is made. This makes sales tracking for the keyword that brought the sale virtually impossible. They do have an Instant Payment Notification feature, but it seems to me not to pass keywords. Any suggestions would be appreciated....
Switch to the express checkout method. This requires that your customers complete the transaction on your website. Right now you're most likely just using the standard checkout and IPN.
The express checkout forces the customer to open a Paypal account, doesn't it? Account Optional means he can pay directly by credit card without having a PP acc. This is for an international account, not US.