Microsoft and Yahoo are poised to make Web-based e-mail more powerful than ever with updates that bring a desktop-style interface to their respective Web mail offerings. We tested betas (currently invitation-only) of Windows Live Mail and Yahoo Mail, and also looked at an open-source newcomer called Zimbra. All three apps use an increasingly popular programming technique called Ajax (Asynchronous JavaScript and XML) to improve on standard Web mail and even Google"s Gmail.
As Ajax applications, the mail clients we tested can preload information and update their displays on the fly. So when you open up an e-mail message, you"ll see it immediately, rather than having to wait for it to download. And when you delete a message, the application can update instantly, even though the delete request is still being processed in the background.