A reader using a slice of bacon as a bookmark? I'd never heard of such a thing until I saw it in the Paper Cuts blog at the New York Times,

http://papercuts.blogs.nytimes.com/2009/01/08/librarian-theres-some-bacon-in-my-book/

I commented that perhaps a slice of bacon is an unconscious statement on the part of the reader, to say that Francis Bacon really did author Shakespeare's plays, or that the writer really "brought home the bacon."

I know I've seen this blog before and have added it to my list of regular reads.