Yahoo! Mail Beta is a web-based email application that combines the rich, responsive interface of a desktop program with the available-from-anywhere convenience of your existing Yahoo! Mail account.
Benefits of Yahoo! Mail Beta include:
* Drag and drop messages into folders for better organization
* A preview pane makes it easier to read your messages
* Speedier Ajax-interface
* Keyboard shortcuts such as Ctrl-S to save a message
* Navigate from message to message with the arrow keys
* Messages open in tabs or new windows so you can multitask
Yahoo! Mail Beta doesn't work in Opera (GMail does), it's pretty fast, loads faster than GMail, but you don't have the feeling you're using a desktop client. For example, scrolling the list of messages takes some time, you have to wait a couple of seconds after you select a message (you only see: "Loading message...").
The built-in RSS reader works very good, it imports your feeds from My Yahoo, but you can't categorize them or move them, you can't export your subscriptions into OPML.
As described on Google Blog
