Well don't let Hacker News overhear you. The specialized lang they used to make and run the site, Arc, is written in Racket.

Moreso than being mainly created for teaching, Racket was created mainly as an environment for creating languages. Its forte is language development and implementation. This is useful in education, because it allowed them to easily create a number of 'teaching languages,' which are all essentially Racket with training wheels.

But that doesn't mean the base language + environment is only useful in education. I might even call it the most usable and productive LISP currently in wide use. (I greatly prefer it over Clojure, for instance.)