Every time i load up Acrobat Reader to view a PDF file, i might as well go get a cup of coffee -- it's a complete dog, and not at all appropriate for viewing lightweight docs over the web.
It's really quite impressive; no separate viewer app is needed, since you can already view FlashPaper docs as long as you've got a Flash player -- which is likely, since ~98% of browsers already have Flash embedded.
To create FlashPaper docs, try the free FlashPaper trial download here, or you can also get it bundled with Macromedia Contribute 3 (free Contribute trial download here). Note that for backwards capability, FlashPaper also allows you to publish in PDF format.
For more info, check out this online presentation on how FlashPaper works.
(nice job Eric & Erik :)