Was it established that Quora stopped using PyPy? My impression was that more parts of the stack are now being written in Scala:

http://www.quora.com/Is-the-Quora-team-considering-adopting-...

"Yes, we're using Scala for some projects at Quora, both big and small. As a programming language, it offers the following advantages: fast, concise, type-safe, object-oriented yet functional, easy parallelism, extensible and built on the JVM. It is also gaining more adoption in the industry and thus getting more support. At Quora, we'll choose the best tools and stack for the product we're building, and that includes our language choices at times."

From talking to Quora engineers, my understanding is that they rewrote the majority of their stack in Scala. They might still be running Tornado (under PyPy) for their realtime connections to clients.