The definition of "reading easily" is subjective. As I noted in my other comment here, Scribd is not very accessible with what is arguably the only screenreader

The definition of "reading easily" is subjective. As I noted in my other comment here, Scribd is not very accessible with what is arguably the only screenreader for OS X, while the original documents (pdf, word, ppt, excel, txt, etc.) were. Not to mention iPaper is flash, which means there's an additional dependency before viewing the document (an issue that could be ignored if it wasn't for the limitations of some platforms like wii and iPhone, but lack of flash/flash lite for iPhone OS is a rant for another day). And speaking of OS X, "firing up a viewer" and bloat makes no sense with PDFKit in Safari where for me downloading and displaying the PDF in my browser is just as fast if not faster than scribd for a lot of the documents I'm looking at. If you were using the embed/email/social aspects of scribd, then fantastic, but scribd gives me nothing useful otherwise and instead just pisses me off with the various problems one can and does encounter. Youtube succeeded because Real, Apple and Microsoft had a fragmented market with all sorts of formats for video, and no central place to aggregate these videos (with the exception of, say, Apple's movie trailers page). Flash videos became popular because nobody had the patience to download entire videos before watching them, or to install RealPlayer/Quicktime/Windows Media Player and have a subpar experience as a result. Put youtube and flash video together and the answer is obvious. However, you don't have the same kind of issue with PDF except for certain bloated viewers on certain platforms and subpar integration (which, I admit, the embed feature of scribd can come in handy occasionally). If your argument were about powerpoint presentations nobody bothered to export to web/pdf, I would then agree that this type of service is useful, but I would also like to point out slideshare. Slideshare does have an accessible website to a large extent and provides a service not well served on any platform. I'm aware Scribd does PPTs too, but I feel Slideshare displays and handles them better. Scribd could learn a thing or two from them.