Actually, performance is quite important for scalability. A lot of sites written in Ruby / PHP have big scalability pains if they get popular. Twitter had to be

Actually, performance is quite important for scalability. A lot of sites written in Ruby / PHP have big scalability pains if they get popular. Twitter had to be re-written from Ruby to Java. Facebook had to completely rewrite PHP's compiler to make it close to a compiled / statically typed language. Joel Spolsky mentioned how StackOverflow only needed 3 servers to run it for a really long time, because it was coded in a compiled language. [1] [1] http://youtu.be/pPJf8KrvJXU?t=22m33s http://youtu.be/pPJf8KrvJXU?t=22m33s