There are an awful lot of articles out there about Web 2.0. Some of the Church sites have already been implementing these principles (for example)...
- Content presented in XML and transformed into HTML using XSLT or JSP (see new LDS.org or Newsroom sites). This also makes it very easy to present RSS feeds (which is the same XML content)
- Multimedia - How many sites you know of that have as much media content in as many languages as the Church does? (see the General Conference page in the LDS.org Gospel Library)
- CSS-driven page layout, rather than HTML tables (this allows that content to be visible on a wide array of browsers and devices)
- DHTML / AJAX - content changes on the pages without having to load a new page from the web server
- Local unit web sites - This may not be the best example of Web 2.0, but it certainly allows church members to collaborate about news and information that affects them and their neighbors.
Anything else?