Those books on "cloud" bookshelf are books prepared by volunteers and supporters, which include public domain PDF books optimized for iPad screen as well as free or sample publications provided by authors and publishers.
CloudReaders also comes with a "cloud bookshelf", where you can download public domain books and comics for free (the number of books is small at this moment, but we are going to add a lot of books soon).
It means you can use CloudReaders to make presentations! (1) Convert your Powerpoint files into JPEG files, (2) ZIP them into a single file, (3) transfer it to CloudReaders, (4) connect you iPad to a projector using iPad Doc Connecter from Apple, and (5) make a presentation.
[NEW in 1.04] Version 1.04 has a brightness control for night reading, and handles large-image CBR/CBZ files much better.
[NEW in 1.05] Version 1.05 offers more immersive reading experience in portrait mode by centering the page, and hiding next/prev pages.
[NEW in 1.03] Version 1.03 supports CBR/RAR files along with PDF/CBZ/ZIP.
[NEW in 1.50] Auto clean-up of Inbox folder, iPhone 5 support, compatibility with iOS6, retina display support (but still optimized for speed).
CloudReaders (TM) is a free book/comic/movie viewer, fully optimized for iPad (and now supports iPhone/iPod touch too!).
[NEW in 1.11] Version 1.11 supports external display.
[NEW in 1.10] Version 1.10 allows users to add one or more tags to each book, which is way more powerful than folders.
It allows you to read any book/comic files in either PDF, ZIP/CBZ or RAR/CBR format transferred from your PC/Mac or downloaded from the Internet.
[NEW in 1.14] PDF/Comic Annotation using neu.Notes (Tap the "Pen" icon on the toolbar).
This version also has a beautiful icon designed by David Lanham (thank you, David!).
If you are interested in participating to this "cloud bookshelf" effort, please contact submit@cloudreaders.com (or just send PDF files).