Hackershelf is inspired by the tradition of sharing links to free books on Hackernews and Reddit. The main problem with both approaches is I inevitably wind up losing links along with the fact that neither of them was purpose-built for book-sharing or discovery, so Hackershelf was built to scratch my own itch.
rez: There should be a way to detect duplicates. Tagging would also help keep the results relevant to my interests. Looks like it's off to a decent start.