Google Docs Viewer is cool firefox addon which lets you view any pdf, ppt, tiff file directly on google documents online at [ docs.google.com ] So with the help of this free addon you can read and view the pdf documents just by right clicking the hyperlinks and choosing "Open Link in Google Docs Viewer".
Currently it offers support for only PDF documents, PowerPoint presentations, and TIFF files.
Note: With this addon For instance, you’ll connect to the Google Docs Viewer over HTTPS if a file is found at https://example.com/file.pdf . An eavesdropper doesn’t know what file you’re viewing as with your default file viewer.
Download Google Docs Viewer For Firefox to read pdf, ppt and tiff file in google docs