The only drawback though it has improved tremendously is that you cannot input titles that you cannot find in their database. It is a rarity now that they have been around a decent amount of time, but it still can happen. In a recent newsletter they stated that at some point in the future will allow it, but right now that is not the case.
If you would like to join all you have to do is go to read.rifflebooks.com/home and sign up! You can create an account using Facebook account, Twitter account or by email. It is no longer a Facebook app.