What reminds you of what? When one reads — or hears about — a book, one almost unconsciously make connections — this book is a little bit like that book. When you tell someone you are interested in some topic s/he will often say, “well, then you should have a look at ….”
I just stumbled across a web resource, http://www.librarything.com/, that implements this as a combination of a personal library catalog and a social network. It allows you, virtually, to surf your own library and connect from books you know to books that are related to it. Users “tag” books creating a interesting way to slice through the database. Try these, for example: sociology, history, philosophy, economics. And it keeps an eye on where a given book is available — libraries, bookstores, online digital sources, used book networks (like abebooks.com).
When I played around with it looking for books on the sociology of information I got a bookshelf that nearly mirrored my the books in front of me on my study’s shelves, but with a few titles I was unfamiliar with :