Here's a summary from the Smithsonian:
A new program aims to change that: Earlier this month, the Digital Public Library of America (DPLA) launched the Banned Book Club, which provides users with free access to titles pulled from the shelves of local libraries.
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The app uses “GPS-based geo-targeting” to stock virtual libraries across the country. After visiting TheBannedBookClub.info to see a list of titles banned in their area, readers can download those books for free via the Palace e-reader app.