BookCrossing's goal "is to make the whole world a library."
It's the upside of globalization: sharing something inherently good and watching how others have taken pleasure in it (or not).
The "3 Rs" of BookCrossing are:
So you share your book and then are able to track what happens to it: where it travels, who reads it, what others think of it, etc.
And then there's bookhunting--the optional, interactive, task-oriented element:
After registering and releasing a book, members have the option of making Release Notes, specifying where exactly (or approximately) they left a book. You can browse through these active releases here, by Country, State, City, and Crossing Zone. When someone finds a book listed here, and makes a journal entry, it will come off this list.