Good for the founders. BTW, although I used to really enjoy Prismatic, I stopped using it because I did not like the Twitter permissions it required on signup (ability to post using your account, etc.). I have been systematically reviewing mobile apps and web apps I use and dropping those that require privileges that don't seem reasonable to me.
Prismatic has some very talented people and they have poured an incredible amount of work into their product. Good for them.
This is another success story for Clojure (Prismatic has released some nice Clojure libs)