First, if you don't have some sort of "master list" that all buyers can get subscribed to regardless of product, go to E-junkie Seller Admin > Account Preferences and make sure you don't have our Aweber integration set up in the Common Notification URL there, as that would receive the buyer's info regardless of item(s) ordered.
Next, bear in mind that if the buyer does not opt-in to receive newsletters when they perform a checkout, we will not submit their info to Aweber. PayPal Standard checkouts will opt-in buyers automatically since they have no way to opt-in or -out, but other checkout methods will show a box the buyer must deliberately check to opt-in to joining your list for the product(s) they purchased.
Finally, once we do submit a buyer's info to Aweber, they will send the buyer an opt-in confirmation email for each list, with a link they must click to confirm they wish to subscribe to that list. If the buyer does not confirm their wish to join a list by clicking its link, they will not be subscribed to that list.