While your point it technically valid it is statistically invalid. With the vast majority of interactive websites handled via CGI, mod_perl or something similar is the solution. To be technically correct one would say that you get benfits whenever the startup time (forking an interpreter, connecting to a DB) forms a significant portion of the total runtime. There are relatively few exceptions to this. Downloads and other streams plus long running processing are among those exceptions. It is not a case of *some*, it is a case of *mostly*

BTW, extra hardware also means more reliability.

Rubbish. Extra hardware actually increases the chances of a failure. Think about it..... If the mean time to failure is 700 days and you have 700 servers you will on average have one fall over every day. Extra hardware only provides uptime/reliability protection if you use that hardware to create redundant nodes with automatic failover and to be frank I don't think we are talking that level. If you use efficient code (mod_perl) included you may be able to *afford* that kind of infrastructure as boxes that would otherwise be working inefficiently can be made to do more work*, freeing resources for redundancy. But even the simplest high availability system really needs 4 nodes - a pair out front to create your redundant load balancer and a pair behind to do the work/provide failover. Of course there a lots of other ways to skin that cat depending on how much downtime you can tolerate.

* Of course caning the hell out of your hardware does not help longevity ;-)