People need to remember that twitter started as a side-project at odeo. Odeo is a Rails app (right?). These guys just used what they knew to get twitter going

People need to remember that twitter started as a side-project at odeo. Odeo is a Rails app (right?). These guys just used what they knew to get twitter going: ruby. No big deal and no surprise at all that ruby (for several reasons) is not the first choice for such a high volume messaging back-end. Who cares. Ruby is a beautiful language. But your pet langugage can't serve all needs, get over it. Scala is a fantastic language that is capable of handling the requirements of twitter's back-end problem domain. Its my understanding that twitter played with quite a few alternatives before settling on scala (erlang based solutions being one). They went with scala. Cool.