US puts out Researched Based Web Design and Usability Guidelines
I came across an article in Government Computer News, a US magazine that targets the government sector. The article dealt with a 292 page report on web design and usability. See article at http://www.gcn.com/print/26_14/44474-1.html?topic=techreport. This report should be of interest to anyone who is designing an redesigning a website including drupal.org.
You might be asking, what's different about the report? The big difference is that for each recommendation it examines the relevant scientific evidence and studies that support the recommendation. That in itself is valuable imho.
The document is free, viewable online by chapter, downloadalbe (192 MB PDF file), or you can order a paper copy (See http://www.usability.gov/pdfs/guidelines.html)
I also have one specific issue with drupal's printer friendly pages. They are not very friendly when the line length exceeds 72 characters. Who do I talk to about this?
Also for those dealing with module documentation or book node content, please chunk your content into smaller paragraphs and use bullets. It's easier on the eye balls and nerves especially if you are trying to implement those instructions at 3:00 am. Thanks.

Irony?
I'm very interested in this topic and excited to look over the report.
That said, is there an irony that they published a report on website usability as a PDF rather than an online book?
Maybe, maybe not
I guess when I see a PDF file of a very few pages that could have easily been present as a simple web page, it's definitely piss poor usability and annoying.
However, if I see a website that provides me a PDF, warns me that its a large file (pages and file size), I am ok with it. At least they are thinking of me. I personally think that some content is just not meant to be scanned online, but needs to be downloaded in a print. Then it can be read and studied. The pdf merely makes the document very searchable and pagination is maintained among all users.