If you design a fibonacci() function, would you make it print the result to STDOUT, or return the result as a return value?
If the specification is to print to STDOUT, a web server needs to make a trick to capture the output using tie, PerlIO or anything else, just like FCGI.pm does, and that's inefficient.
> - Are all the $ENV variables available? (SCRIPT_NAME for example?)
http://search.cpan.org/~miyagawa/PSGI-1.03/PSGI.pod#The_Envi...
> I don't really see what advantages it will bring to framework like Mojolicious for example (they will certainly never ever used any Middleware stuff from the Plack namespace as this is at the heart of their policy
See this post by the Mojolicious author, how to use Plack middleware for ANY Mojolicious based apps http://blog.kraih.com/mojolicious-and-plack
Also for Dancer: http://advent.perldancer.org/2010/22