I think the WhatsApp Erlang angle is a bit overblown.
While they may have a small number of engineers (20 or max 20?), their engineers are probably laser focus in delivering the product (re: no web-app for the longest of time, no RoR vs Django vs Clojure vs Java vs PHP, no React vs Backbone vs etc etc), just back-end: Erlang, front-end: various phones that needed to be supported.
I would attribute their success at their skill set and experience. If you watch Rick Reed presentation in MeetBSD, a few key points to note: Rick Reed is very smart and knows full-stack (minus the browser): from the OS (internal, driver, etc) up all the way to Erlang VM and the WhatsApp backend.
The team had to modify FreeBSD and patch Erlang VM whenever necessary. How many companies have _that_ kind of talent? (e.g.: modify Linux and JVM to make them run faster? or Ruby implementation and PostgreSQL/MySQL while supporting the actual product?). Rick himself has tons of experience writing distributed systems at Yahoo! (using C++ nonetheless...).
While Erlang helps them but in reality, their skill + experience matter more.
While they may have a small number of engineers (20 or max 20?), their engineers are probably laser focus in delivering the product (re: no web-app for the longest of time, no RoR vs Django vs Clojure vs Java vs PHP, no React vs Backbone vs etc etc), just back-end: Erlang, front-end: various phones that needed to be supported.
I would attribute their success at their skill set and experience. If you watch Rick Reed presentation in MeetBSD, a few key points to note: Rick Reed is very smart and knows full-stack (minus the browser): from the OS (internal, driver, etc) up all the way to Erlang VM and the WhatsApp backend.
The team had to modify FreeBSD and patch Erlang VM whenever necessary. How many companies have _that_ kind of talent? (e.g.: modify Linux and JVM to make them run faster? or Ruby implementation and PostgreSQL/MySQL while supporting the actual product?). Rick himself has tons of experience writing distributed systems at Yahoo! (using C++ nonetheless...).
While Erlang helps them but in reality, their skill + experience matter more.