Now you've got me wanting IO::Pipe::Interdimensional.

Threads are way better than processes if you can use them effectively, as you can share data instantly. As long as you're careful about locking everything down, it's fine. BeOS was a great introduction to how massive multi-threading can be a Good Thing.

The only unfortunate part about mod_perl is that 2.0 isn't "threaded" so much as "thread aware". Maybe the Perl 6 mod_perl will fix this and life will be Good. One of my biggest grumbles about mod_perl is that you have all these processes with exactly the same data, and no easy way to share it. IPC::Shareable is only so good.