Interesting W3C Note from January 2003 that I don’t remember ever seeing:
HTTP and URIs are the basis of the World Wide Web, yet they are often misunderstood, and their implementations and uses are sometimes incomplete or incorrect. This document tries to improve this situation by providing a set of good practices to improve implementations of HTTP and related standards (Web servers, server-side Web engines), as well as their use.
The information here is relevant to people who build web apps, not HTTP server implementors — the title is a bit misleading (not actually but practically). I especially like this bit about why short, less meaningful URLs are better than verbose, descriptive URLs. Shortness has become the most important characteristic of URL design in most apps I've built recently; SEO be damned.