Just some quick thoughts:

First, the name is a little close to Goodreads so I'm glad it's not permanent.

Second, your feed should show book reviews from people you follow but browsing any other way should be by book and not reviewer. Latest could show the latest book reviewed, trending could be the most popular books lately, and featured could be books users vote on each week. The books need to be the focus on most pages.

Thirdly, have you considered letting users keep track of their reads on this platform? Would it be possible to store a full list of read books in the json of a weekly post or just store them everytime a user reviews something?
If you do go this route, it would be nice to see something a little more visually appealing then Goodreads. Something I've thought would be neat would be to have a user page look like a library with shelves that store each book. You could create a standard book image, randomize its height then adjust width based on a book's page count. Letting users rearrange books' order on the shelves might be more difficult but would be awesome.

Goodreads is currently the only site of its type, but it has so much room for improvement that it's very possible to build something more engaging and fun than it.