Our book club tends to be a social gathering as much as a discussion group. Usually each meeting entails wine, food and, of course, the book. So we coordinate our reading, our food, wine all through Qlubb. It's just an easy way to manage each meeting and attendance. It's super easy and free.
Users join a group of 6 and rotate books each month...so you contribute your own book and read 5 others that are sent to you each month. It's pretty cool...and it's free. So far I've read some great books.
I hype this site pretty often - it's an e-mail book club (actually, a dozen of them, and you can sign up for as many as you want) that makes weekly selections and e-mails you daily excerpts. It's a convenient way to sample books, and I've found a lot I wanted to read further after getting that taste.