Follow the Reader has a great series (Part I and Part II) going on sites and services that create communities around books, such as BookGlutton and FlashLight Worthy Books. Discussion, rather than community, is the basic unit of connection, in my opinion. Community evolves from simple functions, such as chat and annotation. The explorations going on now will be immensely helpful to turning the e-book from a replication of the printed page to a vital medium for human intellect, entertainment and interaction.
I’m looking forward to seeing future installments. Well worth your reading time.