Interesting and Rich "Design for Usability" Guidelines

The U.S. Department of Health & Human Services offers a rich set of detailed guidelines for designing usable websites.
They are an interesting "package" of resources, especially for first time designers.
As positive aspects, I have found the width of the aspects covered, the pervasiveness of examples and the grounding of the design guidelines with links to research-based evidence.
However, there are some weak points to be noticed. It appears that some guidelines well fit the design of "governmental" or "public" websites only (and probably this is their purpose). They leave little spaces for alternative design decisions (still usable!). They are too "imperative" and do not take into account specific requirements and needs that other families of applications may have.
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