Switching banks is hard. Switching between Yahoo! Mail Classic and the new Yahoo! Mail Beta is easy. In the time it takes you to lift the receiver off the phone and put it to your ear, you could have already switched from the original classic version of mail to the Yahoo! Mail Beta version.
Just have a gander at the top of the page next to the logo in the Yahoo! Mail window. You should see a link under your account name. If you’re using classic mail it says, “Try the new Yahoo! Mail”, or if you’re using the new Mail Beta it says, “Switch Back”.
You are welcome to switch as often as you like, and there’s not a bank fee in sight.
Andrew – Yahoo! Mail Beta Team