Scribd is an online service, also available as application for mobile devices, that allows to upload or read different e-books or other kind of documents.
Google Play Books is a service offered by Google where you can find all kind of titles. There are more than 4 million titles and
On Issuu.com you can find a variety of publications, including newspappers and books. It offers millions of titles, you can read a lot of them
On SlideShare you can read all kind of documents for free. Also features some paid upgrades to upload videos. This site is focused to presentations
Hashdoc is a web site where you can find a lot of titles organized by tags or hashes. Users can share different types of documents
Project Gutenberg is the oldest online library and offers only free e-books in various formats. Users can search by title or browse entire library by
On SlideOnline you can read presentations for free. Discover new content and read it in a high quality format. This site is focused on presentations