Readmill, a social reading app and company based out of Germany, is closing. TechCrunch first reported the news that Dropbox has acquired the app, with plans to shut it down. TechCrunch reported that Readmill's staff would be moving to San Francisco to work for Dropbox, but could not confirm details from Readmill's CEO, Henrik Berggren. PW also reached out to Berggren, who said he is not giving any interviews at this time.

Readmill was one of six tech companies PW first covered in 2013, coming out of that year's SXSW festival. In a letter posted to its users, Readmill said its "story ends here" and that it " failed to create a sustainable platform for reading" despite its belief that the reading experience was "meant to be shared."

New Readmill accounts can no longer be created. For existing users, the company said that, over the next three months, its first priority is "to help you transition to other services and get back to reading." Titles that users bought and/or were reading in their Readmill app will be available for export, Readmill said, in a variety formats. The Readmill app will stop being available July 1.

The shuttering of Readmill, for many in the book industry, brings into question the viability of social reading itself, which has been one of a handful of areas some book-focused startup's have explored. Whether social reading is a technology users want--and a viable platform for earning revenue--is now a larger question.

As for Readmill, its staffers are still hopeful they can do something interesting with social reading at their new company. As they explained: "Millions of people use Dropbox to store and share their digital lives, and we believe it’s a strong foundation on which to build the future of reading. We’re delighted to work alongside this talented team and imagine new ways to read together."