Perl's killer feature is Perl. CPAN is a wonderful achievement, but folks have already mentioned that Perl is not the first language to have a library repository.
Rubyforge is an interesting alternative to Sourceforge for projects in the Ruby language. The gems repository is a growing supply of readily accessible libraries. They are not exactly the same thing, even though they are served from the same place. I know a growing number of Ruby developers who use gems regularly but are only vaguely aware of Rubyforge.
Nobody is usurping anything, and I'm not sure if the comparison is valid.
I have become impatient with certain aspects of the Ruby culture over the years. Ruby is a great language and folks are creating all sorts of interesting projects with it, but many users of the language are stuck in this youngest-child sort of "We're worthy! Notice us! Validate us!" frenzy. Not all of them, obviously, but enough that I can't handle reading the ruby-talk postings more often than about once per week. Yes, Ruby is great. Now shut up and get some work done.