http://martymcgfuraocsgy2a25btl5srhifcdud6m4eiphz2mq6fafttwh7qd.onion
The bookmarklet finds and parses this then (quick and dirty) pulls out likely book title, ISBN, and author and combines these with another couple of options (I tag all my reading posts with “books” and I want the posts to be published by default). Those options are turned into URL query string parameters, as described in IndieBookClub.biz’ documentation and sends your browser over there, where IndieBookClub(dot biz) handles the rest!