Esther Schindler over at CIO.com does a great job picking apart some recent data on Ruby adoption. The (Koders.com) data, which is gleaned from language-specific searches on its code repository site, suggests that Ruby interest is up by a factor of 20 since 2004.
However, as Schindler points out, the Koders.com data may simply reveal the obvious (i.e., the Ruby community is vocal) or the not-so-pleasant (i.e., perhaps Ruby users have lots of need to look for information because of problems with Ruby).
So maybe Ruby is on a roll, or maybe it's not. The Koders.com data is inconclusive on this point. All we really know is that the Ruby community is vibrant and vocal.
But Ruby isn't about to take over the enterprise, where most of the money in software still resides. Java and .Net still rule the enterprise roost. Along with the imperfect Koders.com data, O'Reilly Media's book data points to an upsurge in Ruby development, but we're a long ways off from massive enterprise adoption of Ruby, at least in any way that threatens Java developers.