So - on this site you list 5 books you are willing to swap and 5 books you want to receive.
Ok did that - next.
It gives you the matches for the books you listed that you are swapping away and you get the persons email address and are supposed to contact them to make a swap - although the book they are offering is not necessarily the ones you wanted (but they are ones that they had on their receive list).
So, you are giving them the book they want and you get something else from them in return and eventually when something is listed that is what you want - that person will get your email address.
Not sure how effecient this is or if I will ever receive the titles I wanted.