The W3C Technical Architecture Group (TAG) has published Architecture of the World Wide Web, First Edition. Quoting from the abstract:
The World Wide Web uses relatively simple technologies with sufficient scalability, efficiency and utility that they have resulted in a remarkable information space of interrelated resources, growing across languages, cultures, and media. In an effort to preserve these properties of the information space as the technologies evolve, this architecture document discusses the core design components of the Web. They are identification of resources, representation of resource state, and the protocols that support the interaction between agents and resources in the space. We relate core design components, constraints, and good practices to the principles and properties they support.
It's pretty good stuff overall. Everyone working on the Web, the Semantic Web, or with XML or URIs should read it.
Jens Låås has released version 1.5.4 of xmlclitools, a set of four Linux command-line tools for searching, modifying, and formating XML data. The tools are designed to work in conjunction with standard utilities such as grep, sort, and shell scripts. Version 1.5.4 allows UTF-8 output from xmlgrep. They are published under the LGPL.