The "crossing" or exchanging of books may take any of a number of forms, including wild-releasing books in public, direct swaps with other members of the websites, or "book rings" in which books travel in a set order to participants who want to read a certain book. The community aspect of BookCrossing.com has grown and expanded in ways that were not expected at the outset, in the form of blog or forum discussions, mailing lists and annual conventions throughout the world.