James175: I think what I was asking was pretty reasonable.
Agreed. The way I see it it's just asking for information on how to get site functionality to work as it was meant to be.
I don't know how it's done internally, but if I were to design such a feature I'd not as much take into account what titles the user has already bought, but what ratings he/she has given different titles, and then found other titles given high ratings by others who have given high ratings to the same games as the user (and similiar with low rated titles).
So, if it does work anythig like that, simply give the two games a low/medium rating, and perhaps find one or more games you already know and like, and give them high ratings. It may not help, depending on implementation of this feauture, but it shouldn't hurt either.
Edit:
Blaming the lack of morning coffee yet, but I'm not entirely sure what I replied to here - where is this list of recommendations, anyway? If you're talking about the "customers who bought this also bought" list, it's not personal to you, except regarding what you have in your shopping cart at the moment.
I better get that mug of coffee now..