I came across the long S in the fifth grade, if I recall, during some line of learning about colonial American history. The conversation between the teacher and me, in the middle of class, went something like this:
> Why is the letter S shaped differently?
> If you'd read the sidebar, it says that's the letter S.
> But why is it different?
> It's just an S. We need to move on.
I've never really been curious enough to go look up the Wikipedia article in the ensuing years, but that discourse really stuck with me. Luckily, now that it's been linked here, I _have_ read the Wikipedia article, and have my answer (typesetting). Even if Wikipedia didn't exist in those days, though, it would've been nice to be pointed at an encyclopedia instead of having my question dismissed.