for the sake of users using text readers and visual aides, it's still nice to use the <strong> or <em> tags and then edit those with css so it implies emphasis or strong emphasis when those words are spoken.
http://www.nngroup.com/ has pretty bad typography. they could use some headings since they have none that i can see, and they should change their font size to a px or em value instead of using keywords. the text colour scheme is okay though, if not sliiiightly monotonous and in use of depreciated attributes in the html and "web safe" colours. Some sizes, and maybe some letter spacing in the heading and logo would work wonders too. I'm not going to get started on the other aspects of this site because then it would take so long i would need a publisher and have this post copyrighted and be on oprah.
with the speed of internet connections today, i don't think there's any reason for internal css in place of external for a page other than specificity and even so, you could just be more spicific with your selector to achieve the result. that's a part of what web design is about. being able to structure you page in such a way that everything flows together. all roads lead to rome, but i'd rather walk the well structured straight road instead of having to jump between bridges if that makes sense. it's easier to work if you can manipulate all the css from a single source instead of having to jump back and forth between your internal and external style sheets.
I enjoyed this, but I don't think I will use the font shorthand much. I like to see exactly what is what (control-freak)
I am not sure if one should use relative of absolute units in font sizes. I have several family members who are visually impaired and I think they would like to enlarge the font on any site - although changing the zoom-level seems to work with both relative and absolute
Those I'm likely to use are the relative measurements and the font-variant property.
It seems as though I'm bringing up the rear, and panic is starting to set in!
Onward and upward!