What I've always wondered is why mod_php can be offered on shared solutions, while there is no way mod_perl could. Are the PHP folks being more clever, or just not talking about security? If they're being clever, why can't we? And if we can, why don't we do it? If mod_perl could easily be offered for virtual domain hosting solutions, it would probably put a dent in the proliferation of PHP.
(To abate the flames, I don't mind PHP, the same way I don't mind shell scripts. But I wouldn't use either for anything complex.)
Makeshifts last the longest.