Yahoo Briefcase will be closed on March 30th 2009.. for good!
I just received the following mail. I have completely forgotten about this service too. The last file I have put there was in 2004. It's good to know that Carol Bartz is doing her job.
Dear Yahoo! Briefcase user,
We will be officially closing Yahoo! Briefcase on March 30, 2009.
Until then, we are offering you the opportunity to download your files
back to your computer. You will need to take action before we close,
after which any files remaining on Yahoo! Briefcase will be deleted and
no longer accessible.
Download your stuff and say your good byes!