I'm a bookcrosser and happy to help. Bookcrossing is fun, free, environmentally friendly and generally fab! basically it is a website through which you track where books that you have registered on that site with a unique identification number travel to. You can leave books anywhere you like (not just in cities, but in parks, at bus stops, in cafes, on trains, on the beach, in churches, museums, the hairdressers, pubs - anyehere where there are people basically.). You slap a sticker on a book, leave it somewhere and hopefully somebody else will come along, pick up the book and make an entry at the website, using the special number on the book and tell you where they found the book (not always where you left it!) and what they are going to do with it. Bookcrossers in towns get together monthly to swap books between themsdelves in a more formal way and the website has a lot of forums where you can talk books. I have made some lovely new friends with it and have read a lot of books that I would not otherwise have tried. I still spend £££s on books though! I'm Dorothyredboots on bookcrossing too so feel free to have a look at my shelf on there and see what we get up to.
I'll try to help with any other ???s you have