April 11, 2007
Update [July 3rd]:
It seems like many people are running into this page and when they search for it they find my site. Just for your information this is a problem with Yahoo servers and your account has not been hacked or anything. This is basically Yahoo source code showing up. You can try contacting Yahoo! support if you want it to be fixed.
I logged out of Yahoo! Mail and guess what showed up instead of the normal flashy ads. Yes, their PHP source code: