Yahoo's new e-mail reader is now in public beta [previous review]. It doesn't take very much time with it to come to a simple conclusion: it is a fantastic e-mail application. I found using it nearly indistinguishable from working with a dedicated e-mail application. There's a preview pane. Messages can be dragged and dropped between folders. Right-clicking the mouse does mail-specific things instead of performing browser actions. And there's no longer any concept of paging through your in-box. You can see all of your messages, no matter how many there are, in one big scrolling list. The interface is a bit slower than running an e-mail app on a PC, but not much.
Yahoo Mail Beta also has an RSS reader built into it. It prepopulates your feeds from your My Yahoo page, which is likely both the world's most used and most underappreciated RSS reader, and gives you an alternate way to view your feeds. Some people like reading RSS feeds in e-mail and some don't; with My Yahoo and Yahoo Mail Beta, you can easily go back and forth.
There are Contacts and Calendar buttons on Mail, but only Contacts is truly integrated with Mail. The interface is the same, and you can right-click a contact to begin an e-mail to that person. There's no similar function to create an appointment, though, and when you click the calendar icon in the main Mail navigation pane, it opens a new window to Yahoo's existing Calendar application.
I was not impressed with Yahoo's spam filters. When I fired up my Yahoo Mail this morning, about 50 percent of my junk mail was filtered out; the rest was still in my in-box. On the other hand, Yahoo does run a virus scan automatically before you attempt to download an e-mail attachment.
Yahoo Mail feels like a direct competitor to e-mail-reading software like Outlook or Eudora. It's free, it's fast, and if you're accustomed to using other e-mail applications, your learning curve will be very brief. But there's another school of e-mail, which Google leads. Gmail is a fundamentally different beast. It does smarter things with e-mail, such as grouping messages in a conversation together and converting some types of attachments (PDFs) into HTML for you. It also gives you more space to store your mail. Google doesn't do its thing as prettily as Yahoo does, but it does some things better.