Accessibility aspects of using PDF

PDF files on the web are used more and more, but sometimes they are annoying and very often unnecessary. Joe Clark gives us some Facts and Opinions About PDF Accessibility.
 
(A List apart hosts more interesting articles on for people who make websites!)
 
Joe Clark wrote about accessibility before in his book Building accessible websites, a must-read for making your site accessible to the blind, deaf or otherwise disabled. The book is organized in an interesting way:
 
“Each chapter ends with a summary of action points broken up into three categories. These are basic (easiest, less costly, less time consuming), intermediate and advanced (hardest, most costly, most time consuming) accessibility. This is a good way for it to be presented as it allows people on the lower end to focus on the most important things and also allows people to take it in smaller bites, if they so choose.” (review of the book by Patrick O’Keefe).