"The primary design goals of iPaper were that it be fast, light and easy to use. At 100 KB the iPaper application is about 1/1000th the size of Adobe's Acrobat Reader software, making it an incredibly fast way to view documents," explains Scribd. While the viewer lacks some features from Adobe Reader, most notably a way to copy text, it renders documents at a high quality, preserving the layout and the pagination.
Similar to YouTube, you need to upload your document, wait until it's converted to Scribd's internal format (that shouldn't take more than a minute) and embed the code into your site. Scribd lets you upload multiple documents at a time and it displays useful stats: the number of views, search queries that led to your document, a visitor map and more.
The site also launched a platform "that allows anyone to bring the iPaper experience to their own website." You could add some code that replaces the links to PDF or Office documents with links to Scribd's viewer, without having to convert the documents manually.
All in all, Scribd has one of the best online PDF viewers and could complement Google Docs, which lacks very good document viewers, shared spaces and a community.
{ via GigaOM }