Here's the latest (that we know) about W3. The High-Energy Physics world got its first official announcement of W3 in the CERN computer newsletter released at Christmas, with an introductory article. However, there are already many users of W3 outside HEP!
The first weblog was the first website, http://info.cern.ch/, the site built by Tim Berners-Lee at CERN. From this page TBL pointed to all the new sites as they came online. Luckily, the content of this site has been archived at the World Wide Web Consortium. (Thanks to Karl Dubost for the link.)