[Mithaldu]

CPAN is the killer app for developers because it is: - an archive of libraries for them to use - a publication mechanism - a documentation mechanism - a global distribution mechanism

And most importantly: It provides you globalized automated testing on a variety of systems of anything you upload, through CPANTesters.

Just as an example: I uploaded a module yesterday and now it has 38 tests on as many different configurations already: http://matrix.cpantesters.org/?dist=CGI-Application-Plugin-T...

So not only gives it a very useful and otherwise extremely expensive tool to you, the developer, it also shows you this information about other modules, so it lets you gauge the quality of the modules you are considering to use.

Edit: Also, as an additional goody: The testing culture of CPAN allows development of ancillary tools that analyze the current state of CPAN and highlight modules that are having issues with their tests: http://analysis.cpantesters.org/ This can help generate bug reports for developers who don't have time to figure out exactly why a test failed on an obscure combo and they provide an in for CPAN-Newbies by pointing out to them which distributions could use patches.