Readmill

Readmill seems to want to be the destination for social reading, as it has multiple sharing options and allows you to follow friends from your linked Facebook, Twitter, and/or Tumblr accounts. Users must create an account and log in before using the app, after which they can upload their own DRM-free ePub books to their free 5GB personal cloud and sync any annotations, highlights, and bookmarks to their Readmill account. The service’s website mentions several book store partners that offer the ability to send purchased books directly to Readmill’s cloud, which is useful. Unlike Kobo, the social aspects seem to be Readmill’s primary concern, which makes it even more of a niche app.