For later reading: The cosmos at Britannica.com. The bits I've skimmed read very well.
Britannica would be a fantastic resource if its interface weren't so bloody shit. All they need to do is Xrefer the entire thing and slap Google on top of it. The technology's there, why not use it? Thought: If Google were extended to understand different link types, and Britannica could label "this is a navigation link", "this is an index link", "this link appears on every page", and so on, the system would work wonderfully, if only because the section navigation already tightly connects pages with siblings and parents in the category tree. It's a tiny amount of coding work and some solid thinking in the interface area. Two good people could do it, no problem.