Faced with a steady decline in wireline voice revenues, major telcos such as AT&T (NYSE:T), Verizon (NYSE:VZ), and NTT are betting on the massive growth expected for cloud services to give them a lift. Verizon has shored up its cloud offerings by acquiring Terremark, while CenturyLink (NYSE:CTL) has done so by acquiring Savvis. However, tough competition exists from AMZN, RAX, and others.