All my Yahoo accounts (bizmail and regular) have been reporting a certificate problem:

Server SSL certificate hostname mismatch. Please go to edit screen of Account Setup to revalidate settings.

The workthrough is correct (revalidate)

BUT it poses this forewarning: presented a certificate that belongs to

Certificate Issued To
Common Name (CN)
Organization Unit (OU) Yahoo
Organization (O) Yahoo! Inc.
Serial Number B25A6
Certificate Issued By
Common Name (CN)
Organization Unit (OU) Equifax Secure Certificate Authority
Organization (O) Equifax
Certificate Validity
Issued On Fri May 08 11:25:17 EDT 2009
Expires On Thu Jun 09 14:04:00 EDT 2011
Certificate Fingerprints
SHA1 Fingerprint 9ED4608DAD0BE1A391F8516AF8078CF65E4A8B82
MD5 Fingerprint F445A43E383CE096F512820AF210783E

Accepting this certificate poses potential security threats to your data

this might trouble some folks.