Adobe's Robert McDaniels Responds (Again) to Nielsen Criticisms of PDF

Many of the 'PDF Usability Crimes' Nielsen cites have nothing to do with Acrobat or PDF but are the result of poor design choices. Most of same arguments about poor navigation, large file sizes, and excessive text blocks can be used to describe poorly designed HTML as well. There are some very valid reasons for using PDF's online as opposed to HTML.

McDaniels, Robert. PlanetPDF (2003). Articles>Usability>Software>Adobe Acrobat