Being an avid player of the meta-game that is trading, a couple of humble suggestions:
1)Ive seen a suggestion for a 'multi-game-only' checkbox that would only return 2+ games from each side of matches. That's good, but Id mod it slightly with
a)a user-selectable minimum # of games
b)a way to indicate that a game is large/expensive enough to count for multiple games for this purpose.
2)Visibility of the other party's wishlist priority for items in the trade search results screen. Also, a 'trade priority' for items offered for trade would be useful- help weed out those items with the comment "practically zero trade interest".
[If we did have a 'trade interest' field, it could be added to the trade search function eg "search for trade matches for my 'high trade interest' and 'medium trade interest' items".
3)Geographic search by zip code instead of US state (as a proxy for distance, which I suspect would be more difficult- but that would be cool too). Pretty easy for users to come up with a list of 'local to me' zip codes. Would be cool if the system saved lists of zip codes (either personal, or even publishable/searchable so only one person has to put together the "Kansas City metro area" zip code list).
4)A checkbox or setting for preference for local trading, eg dropdown with "only trades locally", "prefers to trade locally", "prefers to trade locally or multiple items by mail", "trades nationally", "trades internationally".
5)Currently, if I select a subset of my items in a trade search the engine will return any matches from my items marked for trade. Or I can select the "from my entire collection" box and get returns from any possible hit. Id like to be able to check a box so that I can select specific items for a search but return all matches from my collection in the results (ie after finding a match for the items I specifically picked out, the results should show everything from my collection that the other user wants). Sometimes I only find something that I didnt specifically have for trade but that Id throw in to make a deal work after I drill down.
6)Id like to be able to paste into the search windows- both to search for games that I dont already have marked 'want in trade' and to create a custom list of games rather than selecting the ones I want from the list. eg if Im looking for another dexterity game for my collection it'd be nice to do a normal advanced search and then paste the results into a trade search.
7)A way to bind games into obligatory bundles or otherwise link them- we can use comments to indicate that game X should only trade with expansion Y, but a field in each game indicating the other would make that easier. It would also potentially be useful for non-trading purposes, to indicate that game X and expansion Y are stored in the same box etc.
Thanks for the awesome site!