your noble effort will probably fail to gain traction - having to log in, or divulge any info at all to social media is not a good idea as they have a long history of not caring for users, only for ad revenue.

If you don't just want to be a footnote in the history of ereaders, you may want to consider a focus on compatibility issues (see above). I, for one, would never use this app even though the interface looks neat.