Ruby On Rails For Major Sites - Scalable or Not?

When the Twitter folks used Ruby On Rails as a development platform Ruby gained a lot of recognition as a major and growing player in the big time online space. However as scaling issues started to plague Twitter during its explosive growth last year, some started blaming Ruby on Rails, suggesting it was not appropriate for an application of this size that had a major need for speed and stability.

Today TechCrunch is insisting that Twitter is in the process of completely abandoning Ruby On Rails while eWeek's detailed article is insisting they are not, quoting senior Twitter Engineer Britt Selvitelle regarding Twitter moving to another platform:

"Not true in any sense. We use Ruby as our primary language. We have plenty
of back-end architecture in other languages. Especially prototypes. We still
use Rails and have no plans to discontinue this in the future"

Losing Twitter could be a major blow to Ruby on Rails sterling reputation for easy and powerful development tool from small to enterprise level online environments, but based on the story so far it looks like the rumors of Ruby's death have been greatly exaggerated.