When Franklin Roosevelt called December 7, 1941, “a date which will live in infamy,” he wasn’t saying it would be famous. He was telling the world that it was a day that would be remembered for an evil act. When the Yahoo! Style used the word infamy to describe the effect of the Duchess of Cambridge on designers, she was saying she has no idea what infamy means:
Infamy is not a synonym for fame, just as infamous is not a synonym for famous. Infamy and infamous imply notoriety for evil, disgraceful, or criminal actions.