It takes a little away from the story that it took them a lot of time to discover a widely published performance and memory problem with scalas actors.
"after a lot of poking around, we became fairly convinced it was due (at least in part) to the default actor implementation in Scala"
"widely published performance and memory problems with scala actors" - remember the code dates back to November 2009 when that was not common knowledge...
The post was probably a little unclear, I did not understand you poked around to find the oOms in 2009, I just assumed it was more recent as the Clojure post was from September 2011.
No, we didn't hit the OoM regularly until we had more traffic as we moved more sites onto the new system and it wasn't clear that there was an admitted problem with the Scala actors at first either.
These days folks seem much more comfortable about admitting there's a problem with the built-in actor implementation.
"after a lot of poking around, we became fairly convinced it was due (at least in part) to the default actor implementation in Scala"