Hi,
daily traffic: 20,000 - 100,000 unique sessions (medium sites) => Php + an efficient caching system => modperl, but not based on Mason or such "application toolkits"
I don't agree: I had a website running with 20.000 visitors/day, build with Mason (MasonX::Webapp), split into 180 frontend apache an 20 mod_perl backend apache , server load was below 1, on a 1 GB hardware. And I had no need to enable any of mason's caching or performance feature 9staice source etc).
Rolf Schaufelberger