My first post is on the technology that is reconstructing the web. AJAX stands for Asynchronous JAvascript and XML. AJAX lets you scroll around the world using Google Maps. It saves your email as drafts automatically in Gmail. It completes your friends' Email address as you type in both Yahoo mail and Gmail.
AJAX moves the interaction between a web browser and the server into the background. So you don't have to wait for pages to load. Further, since the server only needs to send updates, and not the entire webpage, the interaction is much faster.
AJAX has now been used to create an online Word Processor, that is compatible with Microsoft Word - intuitively called ajaxWrite. AJAX will probably be the backbone for Yahoo's new mail interface (screenshot) that lets you organize mail just like MS Outlook (drag and drop, filter, rules, etc.). Just imagine, you'll be able to compose documents on ANY PC, regardless of the software installed. It's quite possible, that soon the only software required on a PC will be a web browser.
The biggest advantage is that new versions of software can be rolled out automatically and immediately. There will be no need for purchasing software as CDs. Plus, as the software are hosted online, inline advertisements could be served making their usage free.
Downside, an internet connection becomes mandatory.
Further reading: A set of articles that provide an in-depth look at Ajax