This is an absolutely fabulous idea. I think that FastCGI has been
very underrated
in its potential. Its too bad there's no longer any linked-in support
for FastCGI on iPlanet or IIS since
Fast Engines was bought out by Adero. See www.fastcgi.com for the sad
story.
Nonetheless, you can still use the cgi-fcgi program that comes with
the FastCGI
development kit at www.fastcgi.com if you really want to use those web
servers.
The author claims that there's very little performance overhead in
this configuration
but I couldn't find any performance numbers.
Anyway, being able to host an OpenACS site at an ISP running Apache will
greatly reduce costs for some(including me) and probably lower the barrier
to acceptance of OpenACS too. Trying to get an ISP to compile in a module
like mod_nsd into a shared Apache server is an uphill battle in my
experience.
Getting an ISP to allow a FastCGI program to run will probably be a
much easier
task.