In Digital Web Magazine last month (September 16, 2008), Leona Tomlinson of Agoo IT wrote a great article: "Understanding disabilities when designing a website". While some of the information can be found in many places, Tomlinson distills a broad range of information in one article, making it ideal for sharing with those new to Web accessibility. She also organizes it by disability – including the often overlooked cognitive disabilities. Tomlinson provides snapshot statistics of people with disabilities in the U.K. and the U.S. By showing the data in raw numbers rather than percentages, you get – to my mind – a powerful sense of scope. The comments that follow the article are useful as well. Particularly useful is a reference to Ginny Redish and Mary Theophanes' article "Guidelines for Accessible and Usable Web Sites: Observing Users Who Work With Screen Readers" (.pdf) originally published in Interactions, this link is the the authors' version and includes figures not in the ACM publication.