Well Twitter did hire Adam Messinger away from Oracle last year to be VP of Development., and Square has Bob Lee as CTO. (something of a sister company, the CEO jumps between the two every day). Last I heard is that Square still uses Ruby but runs it atop the JVM with JRuby. That information is a year old so take it for what it's worth.
But, that register article is absolutely worthless reporting. I'm not convinced the reporter understands that this "highly optimized Ruby designed for longed-lived blah blah" is really just JRuby (which is as "ruby" as the MRI). Having sat in press rooms at conferences like JavaOne I can personally attest that most of the people covering what we do have zero understand of what we do. Bleh