to find out what the problem is
I couldn't care less if Yahoo! messes up for a day or two. I still have Yahoo! mailboxen, but it's mostly an address to give services I don't want to give my real (relatively peaceful) address.
What concerns me is the possibility that they pulled the plug after noticing China/Russia/America (delete as per your preferences) swiping a copy of everything.
I mean, it's not as if Yahoo! has a great track record here...