Lulu

 Lulu  is a print-on-demand book service that could be used to print a physical copy of their website, as a back up or for longevity.

Anecdotally mentioned in chat, at least one person is planning on using this service to print (a portion of) their website as a physical book.

Advantages

 * Provides an easy-to-use interface to configure printing options
 * Useful for people who do not have printers at home or who do not have a printer that meets their book printing specifications (which is likely if you want a hardback book, for example)
 * You can order one copy of a book rather than having to buy in bulk

IndieWeb Examples

 * has created a printed version of his blog which was printed using Lulu