Comment by iLemming

Honestly, do you really think a company with only 35 engineers could build, scale and sell a product like WhatsUp for even a fraction of that amount but using C++, Java or Python? I seriously doubt that.

Look, I've seen both sides and I know this for sure (this isn't a mere opinion, this is a certain fact) - FP allows to build and maintain products using smaller teams.

You don't have to trust my word, do your research, google "companies using Clojure" (or Haskell, OCaml, Erlang, etc). You will see that either those companies are not too big, or the FP teams in large companies not very large. Skeptics often cite this fact, claiming it to be the proof that FP codebases don't scale to large teams. The truth is - you don't need a big team to build a successful product with FP language. And the number of startups using FP langs is steadily growing.