A couple features discussed on the show:
- ability to create different "stacks" of Perl modules for different environments (development, test, production, etc) or operating systems (Windows, Mac, Linux)
- Version control of your stacks
- "Pinning" which is locking a module to a specific version
- Ability to merge in local modules that you don't want to be available on CPAN
After hearing a description of this, it got me wondering why these kind of things aren't available in CPAN in general? The main reason I can think of for not doing this is that it would vastly complicate the current CPAN set up.
If anyone pins an older version of a module, CPAN would have to keep that available forever. It could also lead to complexity tracking what is a local module not available anywhere else and what is a module available in CPAN in general.