The blessed languages of Amazon are C++, Java, and Perl.
Ruby is replacing Perl, and that's been going on for a few years now (and we have a pretty active RoR community).
stats?
not sure what kind of statistics would be good and not violate the NDA =) but our internal rubyhackers mailing list is one of the busiest lists that I'm on. I myself am not a Ruby fan, so don't know any details.