i searched for fdsc on google and it gave me the same message as on ur screen, seen my screenshot. so dont jump to the conclusion that yahoo is down.
@axlarry, I would tell you wat most of the customer support people tell u to do wen u call them up for internet related issue, "Please clear ur cache and cookies and everything and lemme know if the issue still persist"
Yahoo mail is working fine now. Most probably it was one of the rarest occassions when yahoo was restarting one of their servers and from your location mail.yahoo.com was translated to that dns. Just a possibility.