We used to use Adobe FlashPaper to embed pdfs into our site. This made viewing a pdf  easy, most people have flash installed, right?

No… and chances are, if they don’t have adobe reader, they probably don’t have flash.

A better/free solution would be Google Docs Viewer.

Use Google Docs to quickly view documents online without leaving your browser.

Embedding Docs Viewer into your page, gives you the same usability as FlashPaper, but without Flash needing to be installed. Now we can give our users the ability to view our pdfs, directly in our browser, without any third-party dependencies. (You may also provide a non-embedded url, to open in full screen)

We did run into one problem. We received this error on one of our pdfs:

Sorry we are unable to generate a view of the document at this time

Replacing the spaces in the filename with %2520 solved the issue. %20 and + did not.