I teach English comp to freshmen at the University of Arizona and assign this piece every semester. About a quarter to a third of them don't realize that Rauch is joking. Usually I go through the Google section ("I performed exhaustive research on this question, in the form of a quick Google search. The answer: About 25 percent. Or: Just under half. Or—my favorite—"a minority in the regular population but a majority in the gifted population."") to make this obvious.
I've also noticed a weird gender breakdown: a fair number of guys say things like, "this describes me perfectly!" and a fair number of girls say things like, "this describes my boyfriend perfectly!" It's rare to get responses the other way around. Anything that increases understanding is, in my view, a net good thing.
A poorly written book called "The Introvert Advantage" elaborates on the idea that introverts aren't necessarily shy -- they just need time alone to recharge, while extroverts actually find themselves energized by others and bored alone. Despite the low quality of the writing, I sometimes recommend it to people who have that "ah ha!" moment.