Text Appearance
1. Use dark text on plain, high-contrast backgrounds (4:5)
The author qualifies this advice by beginning with "when users are expected to rapidly read and understand text ..." suggesting that this is not universal, but applies to a specific purpose.
Dark text is preferred to light text (on average, people read dark text on a light background 32% faster than light text on a dark background).
Use a plain (solid) background rather than a textured background, and ensure that there is high contrast, both to ensure legibility.
(EN: eyestrain may be a separate issue. The reason early monitors were light-on-dark rather than the other way around was to reduce eyestrain: a white screen is harder ion the eyes than a white piece of paper)
2. Format common items consistently (4:2)
Formatting applies to font and size (making headers the same font and size on all pages) as well as data formats (using consistent formatting for date, time, phone numbers, etc.)
3. Use mixed case for text content(4:2)
Mixed-case text (standard sentence-case) should be used for long passages of text to maximize readability. Again, all-caps is not banned in all cases - it can be useful to emphasize words, and there is no prohibition against using it in short passages.
4. Ensure visual consistency (4:4)
Typography (font, size, case, etc.) should be used consistently throughout a Web site to provide consistent visual cues to the user.
EN: One exception might be to vary the color to create 'themes' within a site.
5. Use bold text sparingly (3:3)
Bold text should only be used when it is important to draw the user's attention to a specific piece of information. It should not be used for formatting (even used to separate field identifiers from values, bold makes it less readable) and it should certainly not be used for legibility (if text must be bold to be readable, there's a bigger problem: size, font, color)
6. Use attention-attracting features when appropriate (3:5)
The features he's referring to include animation, differences in size, difference in color, different fonts, etc. - anything that makes one bit of text different from the rest that is used on the same context.
What is not clear is when it is "appropriate" - but as with bold text, any attention-getter, done to excess, ceases to draw attention (and may become a distraction or a nuisance)
7. Use familiar fonts (3:5)
Using an unfamiliar font (especially a grotesque) slows reading speed. Even some versions of the standard serif/sans fonts (example, Belwe or Trajan) will decrease the user's reading speed.
EN: Again, this advice is based on the assumption that a particular passage is intended to be read quickly.
8. Use at least 12-point font for content (3:4)
Fonts slower than 12 points (pixels) are difficult to read. For an older audience, 14-point text is recommended.
Regarding print standards specifically, recall that the computer monitor is very low-resolution compared to print, so characters must be larger to be legible.
EN: again, this applies to the main text content of a site.
9. Color-coding and instructions (2:4)
This seems specific to color coding used in information graphics - if it takes a lot of text (more than a few words) to explain the meanings of colors, users find it difficult to understand the meaning of an information graphic.
10. Emphasize importance (2:5)
Changing the font characteristics can emphasize the importance of a word or a short phrase (EN: this seems to be redundant to #6 above)
11. Highlighting information (2:3)
Use a single method to highlight information on a given page.
EN: this seems to speak to consistency, within a page or a site: if one table uses bold text to highlight values, don't use red text in a different table on the same page.