Yahoo co-founder Jerry Yang replaced Terry Semel as CEO. Former EVP Sue Decker now assumes the role of president. ... Digital branding agency Brand New World promoted Brian Brown to creative director, where he will oversee all of BNW's creative work. ... New York-based Bluerock hired former R/GA exec Eleanor Tsang to fill the new position of director of interactive. ... New York creative digital studio rhinofx appointed Maggie Klein of Maggie Klein & Company to East coast sales associate. ... Greg Verdino and Steve Coulson joined crayon, the new digital marketing firm run by blogger/author Joseph Jaffe, as chief strategy officer and chief creative officer, respectively.