SCRIBD

This webside 2.0 it use to share documents, this documents can be private or public.

IPaper is a kind of PDF. You look at the documents, you can also edit and
download.

To register you need a facebook account.

It's a free service, and you can share documents online. Isn't necessary download the documents for review. 

  

The alternatives of this tool are:

1.Issues

2.Cakame

3.Google Docs

http://www.scribd.com/