Robeys thinking behind the Twitter Kestrel project is explained in the developers live journal. This change was driven by the company's need to reliably scale their operation to meet fast growing Tweet rates, already reaching 5000 per minute during the Obama Inauguration. For example, at Twitter, the social networking service, Robey Pointer moved their core message queue from Ruby to Scala. Many existing companies who depend on Java for business critical applications are turning to Scala to boost their development productivity, applications scalability and overall reliability. Code sizes are typically reduced by a factor of two to three when compared to an equivalent Java application. It smoothly integrates features of object-oriented and functional languages, enabling Java and other programmers to be more productive. Scala is a general purpose programming language designed to express common programming patterns in a concise, elegant, and type-safe way.
