Slightly misleading, they don't actually run Racket on the PS3. IIRC, they created a DSL for game logic in Racket and wrote a special compiler for that DSL.
That's still a good example of a "real" program written in Racket, but it doesn't prove that Racket is a good choice for programs that need all the resources they can get.
Also, Hacker News is written in Arc, which runs on the Racket runtime. It handles quite a bit of traffic every day.
It's an ugly-ass buggy website, but that is largely to do with the implementation and PG's propensity for live-modifying production sites in the REPL and not the runtime itself.