Everything's moving to the Web nowadays, as though the World Wide Web (which is merely a way of formatting information using a Graphical User Interface that looks more user-friendly than the old way of putting things up with a DOS prompt) is this Big New thing. It's really not. When I was going to in college in the 1990s (class of 1994) we had these things called "Bulletin Boards" and one of my professors tried to utilize a Bulletin Board to generate more class discussion than we might have had for a a class that met once a week.
Now, I Facebook might be an alternative to doing book groups online, and if we're looking to do outreach that way, Facebook might be a good means of doing that. Facebook would also allow people to be members of book clubs in branches other than the one closest to them. This might be a really good thing in terms of engaging people in their 20s and 30s who would like to participate in book clubs but don't have the time or inclination to get to the physical library.