A package universe for Lisp

Quicklisp is a package manager for Common Lisp that is popular among Lisp programmers. I'm happy to read that one of their secrets to success is quality control in the central distribution:

Quicklisp has a different approach:

• Quicklisp does not use any external programs like gpg, tar, and gunzip.
  
• Quicklisp stores copies of project archives in a central location (hosted on Amazon S3 for reliability and served with Amazon CloudFront for speed).
  
• Quicklisp computes a lot of project info in advance. Projects that don't build or don't work nicely with other projects don't get included.
  

I would quibble with the order of their bullet points, because the last point is overwhelmingly important. It isn't a little side benefit to have a well-defined distribution and to test the members of that distribution against each other. On the contrary, it's a make or break property of the system if you want users to have some level of confidence in the code they're downloading.