I have to say that Messr Bergman is brave. Very brave. I made the mistake of asking him at YAPC what he was hacking on, and it turns out he's messing with memory allocation. I think I may have found a followon to the hypothesis that given enough time, every piece of software will grow to include an XML parser, SMTP client, and web browser. That's upward growth--towards higher complexity and userland functionality. There's also a trend toward downward growth: given enough time, every piece of software will grow to include its own memory management (heap), I/O library (stdio), and database storage system (filesystem)--every program is destined to have its own operating system underneath it.