A new online platform known as Copia has launched, combining the functions of e-bookstore and social media network. Yesterday's article in Mashable provides a nice overview of what Copia is attempting to do. From the article:
After creating an account, users can immediately begin following and inviting people from their existing social networks, including Facebook, Twitter() and Goodreads, and connecting with users with similar tastes as they tag books they like. Users can also join discussion groups that align with their favorite subjects and genres, such as mystery or Victorian, and opt to follow those whose discussions they enjoy most to see what books they’ve read and are reading (privacy settings permitting).
The website can be found here.