DjVu Does What PDF Can't (Score 1)

Here are just a few of the things that DjVu can do that PDF cannot:

1. Encode a 20MB color scan into a 100-200K file, and still produce a good-looking image.
2. Encode a 300 dpi B&W scan into 17K, and still be able to read the image.
3. Create separate image and data layers.
4. Create a multi-page document either as a single file, or as a linked list of indivdual pages, with a file for each page.
5. Construct a URL that will drop a user into the middle of a document (page 50 of 100, for example), without losing the context of the other pages.
6. Provide automatic installation of the free DjVu viewer without sign-up forms that harvest my customer's email addresses
7. Zoom and pan on the fly.
8. Convert to other file formats such as JPEG.

For my money, DjVu is a superior file format that has been nicely tuned for the web. PDF was optimized for print pre-press, and it shows.