Distributed Proofreaders (DP) is a project to support the development of e-texts for Project Gutenberg. Public domain works are scanned by the project managers and the images are run through optical character recognition (OCR) software. Then individual pages are made available for volunteers to proofread by comparing the scanned page and the OCR output on one screen, thus distributing the time-consuming error correction process. Each page goes through two rounds of user proofreading, followed by post-processing, where the book is prepared for upload to Project Gutenberg. The editing process is similar to the Christian Classics Ethereal Library, which predates it by several years but is focused on the narrower topic of Christian texts.
Distributed Proofreaders was founded by Charles Franks in 2000 as an independent site to assist Project Gutenberg. Distributed Proofreaders became an official Project Gutenberg site in 2002. In October 2004, Distributed Proofreaders posted their 5,000th book to Project Gutenberg; about 300 new books were being finished each month. DP-contributed books comprised more than a third of the 13,677 books in Project Gutenberg at the time.
Among many other works, Distributed Proofreaders is currently working on producing a complete electronic edition of the 1911 Encyclopedia Britannica, the volumes of which will be available on Project Gutenberg as they are finished.
In January 2004, DP Europe started, hosted by Project Rastko. This site has the ability to process text in Unicode UTF-8 encoding. Books proofread are centered mainly on European culture, with a large proportion of non-English texts.