Of course, when I said "extremely" above, that means that it lacks everything other than webkit. It has no bookmarks, no history, not even persistent cookie handling. All of those features are expected to be handled by external scripts. That would be fine if it came with scripts that worked, but most of the supplied scripts depend on dmenu, or are unfinished. And even the lack of useful scripts would be fine if the interaction between helper scripts and uzbl were documented, but they aren't.
So in order to get anything done, you have to go diving into uzbl's source — a monolithic ~2700 line C file. The code is poorly organized, with poorly designed regexes and comments that have more questions than answers. It is, in my professional opinion, a huge glob of hacks. It brings me to an idea I thought up the other day, which I'd like to call "Black's Rule":
"For any programming language X, you should not have to understand X to use a program written in X."
After spending a day trying to write a persistent cookie handler, diving through poorly written C, and having no idea why it wasn't working, I've given up on it. I'll come back to it some time later, hopefully after it has matured. I like the idea of a web browser that acts like a tool, but only if the interactions with that tool are properly documented.