Interesting.

Interesting, however these are Not Typefaces but interactive typographic algorithms.

Smart fonts can indeed respond to text, but primarily as letter form content, not lexical meaning.

Typography that responds to the reader is another matter.

Some type designers have used OpenType substitution code to implement such effects, most notably Amy Papaelias: http://www.typetalkfonts.com/typetalk_demo.html

Just and Erik described Twin in 2002:
“Twin is not really a typeface, but more an application that runs on the web.”
http://letterror.com/portfolio/twin/index.html

Not Typefaces... I think I need to go make some Not Fonts...