Sarah Fay, former CEO of Aegis North America, has joined the board of advisors of Cambridge, Mass.–based startup Micronotes, an interactive direct marketing firm. Fay, who resides in Boston, is a digital advertising veteran. Before taking on the Aegis North America role, she was CEO of Carat, Aegis’ flagship media brand. Before that, she was credited with helping build the company’s digital agency Isobar into an industry force. She left Aegis in 2009.