Yahoo CEO Marissa Mayer is trying to nab Henrique De Castro, a top advertising executive, away from her former employer Google. De Castro could be named COO of Yahoo or have a leading role in its advertising and media units. However, De Castro has denied woos from Yahoo before: former Yahoo CEO Scott Thompson attempted to take him from Google but was denied. If De Castro is brought on board at Yahoo, there might be some rekindled friction between he and current head of revenue Michael Barrett, who worked with De Castro at Google. (AllThingsD)