When I get a new address to send a postcard to, I always look at the Dutch postcards that the receiver has favorited. Sometimes there is a postcard between the favorites that I already sent to another postcrosser. Most of the time I have more than 1 postcard of a topic on stock, so for the receiver I think that it is nice when I send one of the favorites, if he of she hasn’t received it yet from somebody else.
I’ve been thinking if it would be possible if the site, or the mail that is send to the sender when there is chosen for a new address to send a postcard to, mentions the by the receiver favorited postcards of the sender. If they are there of course. 
For example: I sent postcard NL-5058395 to Russia. Another postcrosser in the USA favorited this postcard. A few weeks later I got the address of this person in the USA, and I sent her the same postcard (NL-5087335) because I did have another one on stock.
It’s happened to me a couple of times, and I love it. Sadly, in at least one of the cases, I didn’t have the same postcard to send them
I also had it several times in the past. Of course it can happen that you don’t have the same postcard, but if you do have another one, it could make another postcrosser happy, I think.
Most postcards I only have once. So it would be little useful - but a lot of work for the admins - to mention “favorite cards sent by the sender”. And, what is more, often I find cards on a favorite wall having been sent by any sender to somebody else (not the receiver, but it’s on his/her wall). I had this a couple of times, and I really love being able to send a card from the receiver’s favorite wall.
What makes it a bit exhausting is when you have to click yourself through hundreds - or even thousands - of cards (sent from your country) to see if the receiver has already got my “chosen” card, or if he / she has a card on his wishlist-favorite wall - but received by someone else. If you are from a “rare country” this might be no problem, but I’m not …
I drafted a topic, but then found that this one already existed 
When I view someone’s Favorites wall, I’d like to be able to see if they favorited any of my (sent) postcards. For officials/RRs/tags, this feature would be convenient, so I can send one of those cards to them (if their favorites wall is used as a wish list).
It would also work if I could search my “Popular” tab by username, to see if that member had favorited any of my sent cards.
In a broader sense - when I view someone’s official profile, I’m interested in seeing if I’ve had any interactions with them, i.e. if I’ve sent an official card to them before or received one from them, if I’ve favorited any of their cards, and if they’ve favorited any of mine.