As you may be aware, Project Gutenberg is an effort to provide free ASCII copies of out-of-copyright works. Run by volunteers, they hunt down out-of-copyright works, scan them, apply OCR, and proofread them (OCR isn’t perfect, after all).
Project Gutenberg started in 1971 — long before the web — and it becomes more modern as technology advances. It used to be that proofreading was done “by hand”. However, there’s now a Distributed Proofreading effort:
This site provides a web-based method of easing the proofreading work associated with the creation of Project Gutenberg E-Texts. By breaking the work into individual pages many proofreaders can be working on the same book at the same time. This significantly speeds up the proofreading/E-Text creation process.
When a proofer elects to proofread a page for a particular project, the text and image file are displayed on a single webpage. This allows the text file to be easily reviewed and compared to the image file, thus assisting the proofreading of the text file. The edited text file is then submitted back to the site via the same webpage that it was edited on. […]
So, now anyone can become a volunteer proofreader. And, I’m considering helping out. Sure, I may not have time to go through many pages, but those would be pages that someone else wouldn’t have to proofread.