I had seen the rumors for a while now floating around that Yahoo! was going to introduce a new mail client with RSS capabilities, but I guess I overlooked that it was also going to be an AJAX based application. For what its worth, here is my opinion.
It’s buggy. It locked up my browser (Firefox 1.5 / Mac OS X) while just clicking on a few links and the operation is a bit clunky and slow. But that is all the bad I have to talk about for the time being. I have only really played with it for a short time but seem some cool potential with it. It operates much like a desktop application should with dragging and dropping of a message (or messages) into folders. I was also able to browse and delete my mail with the arrow and delete keys. The browser auto checks for new mail so no need to refresh, it will just show new mail as it arrives. I guess I should also mention that you can open multiple emails (in tabbed browsing format) and click between them and a new message compostion window if you need to see multiple emails. The right click while in the Yahoo! Mail Beta also functions as it would in a desktop application with such features as ‘reply to sender, reply to all, mark as spam, etc’.
Another cool addition, as you can see from the screenshots, is that of RSS integration. It seems to have pulled in my ‘My Yahoo!’ subscriptions for display inside of the mail application. While there doesn’t seem to be any special support for podcasting (it just reads the RSS feed as a normal news feed) I did have a lot of trouble subscribing to Podcast RSS feeds. It kept telling me the feeds were invalid (mostly with feeds linked to a WordPress Blog).
So my final opinion: It still needs a lot of love. They are on there way to making it cool, but the hang and drag time frightened me a bit. One thing I just can’t stand is being afraid I am going to lose data…and when I hit a link or go to a new page in the Yahoo Mail Beta I feel like it could crash at any second and I would lose whatever i was doing at that point.