:So what does this mean for the use of Disqus by public sector web managers, whose sites have to be squeaky clean on accessibility? In my view it means we can still use it, but with care, doing the following as an absolute minimum"
Run instant usability studies for your website using your real users. You can get it up & running in seconds with one line of javascript, and immediately watch movies of your users’ browsing sessions to analyze their behavior. Free to start, and if you find it useful, you pay only $0.05 per recorded user.
The Portable Document Format (PDF) developed by Adobe can be made accessible, but it very much depends on how the original document is designed. If it is a poster created in a publishing application, scanned or saved from a Word document and locked down for copyright reasons then saved as PDF, it is liable to act in the same way as a picture. This means the text cannot be read by a screen reader or adapted for easier reading. It is appreciated that the concept of the PDF is to ensure that printed or saved versions of a document remain as the author intends, but there are ways to help the reader who uses assistive technologies or requires different formats of the text and graphics.