Ok, I'm getting confused then... The article uses the Meyers-Briggs definitions.

I'm struggling to find the definition you're using. For example I found this:

    "Introversion is not the same thing as shyness but it is 
    often mistaken as such by extroverts, who may find it 
    difficult to relate to introverted tendencies. Introverts 
    prefer solitary activities over social ones, whereas shy 
    people (who may be extroverts at heart) avoid social 
    encounters out of fear." [1]

Yet if I understand you correctly, there is another definition of introversion that equates introversion with shyness. Can you provide a link or expand your explanation?

[1] http://en.wikipedia.org/wiki/Extraversion_and_introversion