OTOH, without activestate set up, the plugin would be very hefty, because you'd have to basically install perl somewhat... perhaps a binary distribution that was self contained could be rather win32 universal... I'm not sure.
Regardless, the download would be very small for almost all "applets" ... :) ... it's the plugin download that'd get you. It'd basically activestate, with a small package management setup and mime type.
The biggest problem would be getting anyone to set it up. Perl's *way* too powerful to just download something automatically from any site and execute it. :) Gives "Microsoft Free Fridays" a brutal edge to it, as soon as someone starts using malicious system calls. :)